How to Set Up Custom Domains and Email Authentication for Online Course Platforms: Complete 2025

David Zenler Author

Sep 30, 2025 |

Set up custom domains, DMARC authentication, and professional branding for your online course platform in under 2 hours. Increase email deliverability

Setting up custom domains, DMARC email authentication, and professional branding for your online course platform takes under 2 hours of active work and increases email deliverability rates from approximately 60% to 95%. This guide covers the four technical foundations that establish professional credibility and ensure your course emails reach student inboxes rather than spam folders.

TL;DR: What You'll Accomplish in This Guide

Custom domain setup requires 10 minutes of active work (plus up to 48 hours for propagation). DMARC authentication takes 5-10 minutes to configure three CNAME records. System email personalization requires 45-60 minutes. Together, these foundational setups increase perceived professionalism and email deliverability before you launch your first course. Complete all four tasks in one 2-hour session to avoid student trust issues that cost course creators an estimated 30-40% of potential enrollments.

Why Do Custom Domains Increase Course Creator Credibility?

First impressions equal trust in online education. When students see emails from generic domains like gmail.com paired with platform subdomains like yoursite.newzenler.com, it creates immediate credibility questions. According to email security research, 94% of cyberattacks begin with phishing emails, making people scrutinize sender domains more carefully than ever before.

Generic platform domains signal amateur operation to potential students. Professional course creators use custom domains that match their business brand across all touchpoints—website, email, and marketing materials. This consistency builds the digital footprint that establishes trust before students ever see your course content.

Custom Domain vs Platform Subdomain: What's the Difference?

Moving from a platform subdomain to your own custom domain is comparable to operating from a branded office building versus a rented co-working space with someone else's logo on the door.

How Do I Set Up a Custom Domain for My Course Platform?

Should I Use a Primary Domain or Subdomain?

If you have an established website on WordPress or another platform, use a subdomain specifically for courses without disrupting your main site. For example, training.yourbusiness.com for your course platform while yourbusiness.com remains your main website.

If you're building a course-first business, use a primary domain where your course platform is the main destination.

Step 1: Purchase Your Domain Name

Most non-keyword-rich domains cost $10-15 annually from providers like GoDaddy, Namecheap, or Hostinger. Avoid unnecessary add-ons during purchase—platforms will try to sell website builders, email packages, and premium features that can inflate your purchase to $500.

After first-time domain purchase, you'll receive a verification email confirming legal ownership. You must respond to this verification or your domain will be blocked by domain registrars within 15 days.

Step 2: Configure DNS Records (The Technical Part Made Simple)

DNS records function identically across every hosting provider worldwide. Whether your provider labels them "DNS records," "Domain Name Servers," or "Domain Management," the actual record types (A records, CNAME records, TXT records, MX records) work exactly the same way.

To connect your custom domain:

1. Access your domain provider's DNS settings (usually under Domains > Manage > DNS)
2. Create a new CNAME record
3. Set the host as "www"
4. Set the target/value as your platform's assigned URL (e.g., yoursite.newzenler.com)
5. Save the record

Before making any DNS changes, screenshot your current DNS panel. This allows you to revert changes if conflicts occur.

Step 3: Set Up the Critical Redirect (Most Course Creators Skip This)

67% of course creators complete domain setup but forget to verify their domain works both with and without "www" in the URL. Without proper redirect configuration, students clicking links without the www prefix encounter error pages.

To set up the redirect:

1. In your hosting provider, locate the "Redirects" section
2. Add a redirect from your non-www domain to your www domain (or vice versa)
3. Save the redirect

Most hosting providers process redirects within one hour, though they can take up to 48 hours.

Step 4: Test Both URL Versions

Open an incognito browser window and test:

• yourdomain.com (without www)
• www.yourdomain.com (with www)

Both should load your course platform. One version should automatically redirect to the other.

Domain Setup Timeline: Active Work vs Waiting Time

• Active work time: 8-12 minutes
• Propagation time: 5 minutes to 48 hours (average: 2-6 hours)
• Total elapsed time to completion: Usually same day

What Are DMARC Records and Why Do Course Creators Need Them?

DMARC (Domain-based Message Authentication, Reporting & Conformance) records authenticate that emails sent through your course platform actually originate from your domain. Email providers like Gmail and Yahoo check DMARC records before delivering messages to inboxes.

Without DMARC authentication, your course emails are 3-4 times more likely to land in spam folders. According to 2024 email deliverability research by Validity, properly authenticated emails achieve 95% inbox placement compared to 60-70% for unauthenticated emails.

How Do I Set Up DMARC Authentication in 10 Minutes?

DMARC setup requires adding three CNAME records to your DNS settings. The process follows the same DNS configuration you used for custom domain setup.

Step-by-Step DMARC Configuration

Step 1: Update Your Course Platform Email Settings

1. Navigate to Site > Integrations > Email Settings
2. Change your default email address to match your custom domain (e.g., hello@yourdomain.com, not hello@gmail.com)
3. Also update your account profile email to match
4. Save changes

Remember: After changing your account email, you must use the new email address for all future logins.

Step 2: Access Email Domain Authentication

1. Go to Site > Email Domain Authentication
2. Click "Authenticate Domain"
3. Your platform will generate three CNAME records with unique host and value pairs

Step 3: Add CNAME Records to Your DNS Provider

For each of the three CNAME records:

1. Copy the "host" value from your platform
2. Copy the "target/value" from your platform
3. Open your DNS provider's settings
4. Create a new CNAME record
5. Paste the host in the "Name" field
6. Paste the target in the "Value/Target" field
7. Save the record
8. Repeat for all three CNAME records

Step 4: Verify Authentication

After adding all three records, click "Verify" in your course platform. Most platforms confirm successful authentication within minutes, though DNS propagation can take up to 24 hours.

How Can I Test My DMARC Records Are Working?

Use free verification tools like PowerDMARC or MXToolbox:

1. Visit a DMARC checking tool
2. Select "DMARC Record" as the record type
3. Enter your domain without the www prefix
4. Run the test

The tool will confirm if your DMARC record is properly configured and show your DMARC policy settings.

Why Do My Course Emails Still Go to Spam After DMARC Setup?

DMARC authentication solves technical deliverability, but email content also affects inbox placement. Even with perfect authentication, certain content triggers spam filters:

Content that reduces deliverability:

• Excessive use of dollar signs or promotional language
• "Click here" calls-to-action (use descriptive link text instead)
• Multiple large images (increases email weight)
• ALL CAPS text or multiple exclamation points
• Phrases like "act now," "limited time," or "free money"

Gmail and other providers increasingly use AI-powered filtering that analyzes email content sentiment. Marketing-heavy language gets filtered to promotional folders even from authenticated domains. Keep emails lightweight, valuable, and conversational rather than salesy.

According to Litmus's 2024 Email Client Market Share report, Gmail processes 28% of all email opens globally, making their filtering algorithms particularly important for course creators to understand.

What Email Address Should I Use for My Course Platform?

Your course platform email address should match your authenticated custom domain. Using a different domain for your email address than your authenticated domain creates conflicts that reduce deliverability.

Best practice alignment:

• Custom domain: courses.yourbusiness.com
• Authenticated email: hello@yourbusiness.com
• Profile email: hello@yourbusiness.com
• All three should share the same root domain (yourbusiness.com)

Why this matters: When email providers check DMARC authentication, they verify the sending domain matches the "from" address. If you authenticate yourbusiness.com but send from gmail.com, authentication fails and emails go to spam.

How Do I Set Up Professional Branding on My Course Platform?

Professional branding creates visual consistency that students recognize across your course site, emails, and marketing materials. Inconsistent branding makes students question whether they're on the correct site or if pages belong to different businesses entirely.

Configuring Brand Colors and Fonts

Font Selection Process:

1. Navigate to Site > Branding > Font Sets
2. Choose fonts for headings (large titles) and body text (paragraph content)
3. Select font weights (regular, medium, bold)
4. Also configure fonts for your curriculum player (where students watch course content)
5. Save settings

You can upload custom .waf font files if you have specific brand fonts, though most course creators use the platform's included font library.

Color Configuration:

1. Access Site > Branding > Colors
2. Configure colors for:
   • Header (top navigation area)
   • Footer (bottom site area)
   • Body content (main content area)
   • Buttons (call-to-action elements)
   • Links (clickable text)
3. Ensure sufficient contrast between text and background colors
4. Click Save at the bottom of the settings panel
5. Refresh your site to see changes

Common color configuration mistakes:

• White text on white backgrounds (invisible text)
• Button text matching button background color (unreadable buttons)
• Link colors identical to regular text (students can't identify clickable elements)

Why Can't I Just Set Colors on Individual Pages?

You can override global brand colors on individual pages, but setting global defaults saves 15-20 minutes per page of manual color selection. Without global branding, you'd need to manually configure button colors, link colors, and text colors three or more times per page.

Global branding also ensures consistency—when you update your brand colors globally, all pages update simultaneously rather than requiring manual updates to dozens of individual pages.

How Do I Add My Logo and Favicon to My Course Platform?

Favicon Setup (The Small Browser Tab Icon)

Your favicon is the small icon appearing in browser tabs next to your page title. Course creators frequently forget to change the default platform favicon, leaving platform branding visible in student browsers.

Favicon specifications:

• Dimensions: 512x512 pixels (square)
• File format: PNG
• Background: Transparent (if using premium design tools)
• File size: Under 100KB

Create your favicon in Canva or similar design tools using your logo or brand mark, export at 512x512 pixels, then upload to Site > Branding > Favicon.

Logo Optimization for Course Platform Headers

Logo specifications:

• Recommended width: 760-790 pixels (matches email width standards)
• Height: Variable based on logo aspect ratio
• File format: PNG with transparent background
• Orientation: Horizontal logos display better than square logos

Why horizontal logos work better: Square logos create excessive white space above and below the logo in your header navigation, making menus appear unbalanced. If you have a square logo, reposition it horizontally with your business name or tagline to the right of the logo mark.

To upload your logo:

1. Navigate to Site > Branding > Logo
2. Upload your logo file
3. Refresh your site
4. The text-based site name will be replaced with your logo image

If your logo appears too large or too small in the header, resize your source file in a design tool rather than using CSS to scale it—this ensures optimal quality across all devices.

Why Do I Need to Customize System Emails?

System emails are automatically sent when students register, reset passwords, enroll in courses, or trigger other platform actions. These emails use default platform templates with generic messaging unless you customize them.

System emails students receive:

• Welcome emails after account creation
• Password reset emails
• Course enrollment confirmations
• Payment receipts
• Subscription renewal reminders
• Course completion certificates

These communications are often students' first interaction with you—before they access any course content—making them critical for establishing your brand voice and building trust.

How to Personalize System Email Templates

To customize system emails:

1. Navigate to Site > Languages > System Emails
2. Select each email template
3. Rewrite the message in your brand voice
4. Maintain dynamic personalization tags (student name, course name, school URL)
5. Add your logo to email headers
6. Include a personal signature at email footers
7. Save each template

Dynamic personalization tags to keep:

• {school_name} - Your course platform name
• {school_url} - Link to your site
• {student_email} - Student's email address
• {student_name} - Student's first name
• {password_reset_link} - Required for password reset emails

Do not delete critical information like password reset links or login instructions—students need these functional elements even as you personalize the surrounding message.

Time investment: Personalizing all system email templates requires 45-60 minutes. While time-consuming, this one-time investment ensures every automated communication reflects your brand voice for the lifetime of your course platform.

Adding Handwritten Signatures to Course Emails

Personal signatures increase perceived authenticity in course emails. Rather than using your actual signature (which could be copied), create a signature-style image using handwriting fonts:

1. Open Canva or similar design tool
2. Type your name in a handwriting font
3. Export as PNG with transparent background
4. Upload to your media library
5. Insert the signature image at the bottom of email templates
6. Copy and paste the signature across all email templates

This adds personal touch while taking under 5 minutes to implement across all system emails.

How Do I Change Dynamic Text Labels Like "All Courses"?

Dynamic text appears throughout your platform wherever the system automatically generates labels—course listings, navigation menus, checkout pages, and student dashboards. You can customize this language to match your brand terminology.

To change dynamic text labels:

1. Navigate to Site > Languages > Custom Language
2. Identify the text you want to change on your site
3. Copy that exact text
4. Paste it into the language settings search box
5. Click Search
6. Locate the matching label
7. Update the "value" field with your preferred text
8. Save changes

Example customization:

• Change "All Courses" to "My Memberships"
• Change "Purchase" to "Enroll Now"
• Change "Sign Up" to "Join the Community"

The search function finds labels by exact text match, so copy text precisely from your site to locate the correct language setting.

How Long Does Complete Platform Setup Take?

These are site-specific, one-time configurations. If you operate three separate course sites, complete the setup process independently for each site—settings don't transfer between sites on the same account.

Can I Have Different Branding for Multiple Course Sites?

Each course site maintains completely independent settings:

• Separate custom domains
• Independent brand colors and fonts
• Unique logos and favicons
• Different system email templates
• Isolated student databases

Nothing is shared between sites on the same account. Switch between sites using the dropdown menu in your admin area.

This allows course creators to operate multiple brands from one account—for example, a fitness coaching business and a separate business consulting site with entirely different branding.

What Happens If My Domain Registrar Goes Out of Business?

Most domain registrars sell their customer base to another provider rather than simply shutting down. When you register a domain, you're contracted as the legal owner with registration information recorded by ICANN (Internet Corporation for Assigned Names and Numbers).

If a registrar fails, ICANN maintains processes to protect domain ownership:

• Check WHOIS lookup to identify your domain's registrar
• Contact the registrar to transfer your domain to a new provider
• ICANN will intervene if necessary to ensure you retain ownership

This scenario is rare—major registrars like GoDaddy, Namecheap, and Hostinger have operated for 15-20+ years. The bigger risk is using extremely small, new registrar companies with uncertain stability.

Domain ownership protection timeline: If you must recover a domain through ICANN intervention, the process typically takes 60-90 days with proper documentation of ownership.

Frequently Asked Questions

Q: Can I change my custom domain after initial setup?

Yes. Disconnect the existing domain by removing the CNAME record from your DNS provider, update your platform settings with the new domain, and reconnect following the same setup process. This takes 10 minutes and doesn't require platform support intervention.

Q: My domain works with www but not without it—how do I fix this?

Set up a redirect in your hosting provider's redirect settings that sends all non-www traffic to your www version. This is Step 3 in the custom domain setup process that 67% of course creators skip.

Q: What should I do about students who signed up with incorrect email addresses?

Include help page links in your emails so students can contact you when they don't receive communications. You can manually correct email addresses in student profiles. This commonly occurs with misspelled Gmail addresses or incomplete domain extensions (.co instead of .com).

Q: How long does DMARC authentication actually take to start working?

Adding the three CNAME records takes 5-10 minutes of active work. DNS propagation takes 1-24 hours for email providers to recognize your DMARC records. Most course creators see improved deliverability within 6-12 hours.

Q: Should I complete these setup tasks before or after creating course content?

Complete foundational setup before launching courses. These configurations establish professional credibility that affects whether students trust you enough to purchase. Creating courses with generic branding then retrofitting professionalism later wastes time and may cost early enrollments.

Q: What size should my course platform logo be?

Use 760-790 pixels width as a starting point, matching standard email width. Horizontal logos (wider than tall) display better than square logos. For square logos, reduce to approximately 300x300 pixels to avoid excessive header space.

Q: How do I verify my DMARC records are configured correctly?

Use free tools like PowerDMARC or MXToolbox. Select "DMARC record" as the test type, enter your domain without www, and run the verification. The tool confirms proper configuration and shows your DMARC policy settings.

Q: Why are my emails still going to spam after DMARC setup?

DMARC solves technical authentication but doesn't control content filtering. Avoid promotional language, excessive images, and marketing phrases that trigger content-based spam filters. According to Validity's 2024 research, content triggers cause 30-40% of authenticated email deliverability issues.

Q: Can I use my existing Gmail or business email instead of creating a new domain email?

Technically possible but not recommended. Using an email address from a different domain than your authenticated custom domain undermines DMARC authentication and sends 40-50% of emails to spam folders.

Q: What's the difference between a primary domain and subdomain for courses?

A primary domain (yoursite.com) makes your course platform your main web presence. A subdomain (courses.yoursite.com) keeps your main website separate while adding courses as a dedicated section. Choose based on whether courses are your primary business or an add-on to existing services.

This guide is based on a live technical workshop conducted by Zenler platform education specialists Kevin and David in September 2025, who collectively bring over 30 years of experience in online course platforms, email deliverability, and digital marketing infrastructure. The setup processes documented here have been tested with thousands of course creators across multiple platform configurations and hosting providers.

Categories: : Zenler Course Creation, Zenler Marketing Help/Advice, Zenler Website/Development