What are common CNAME misconfigurations?
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You've added the CNAME record, your ESP says it's pending, and now you're stuck waiting and wondering if something went wrong. Nine times out of ten, one of these six issues is the culprit.
Typo in the target hostname. Your ESP gives you a tracking hostname to point your CNAME at. One wrong character and every tracked link in your campaigns breaks silently. Copy-paste the value directly from your ESP dashboard rather than typing it by hand. Then double-check it in your DNS editor before saving.
Added to DNS but never verified in the ESP portal. Setting the record in your DNS host is only half the job. Most ESPs require you to go back into their dashboard and hit a "verify" or "confirm" button after the record propagates. Skip that step and SSL won't get provisioned, which means your tracking links will either throw a certificate error or fall back to the non-branded default.
A record conflict at the same name. A CNAME can't share a hostname with any other DNS record type, including an A record. If you already have an A record at, say, click.yourdomain.com, your CNAME won't resolve. Remove the conflicting record first, then add the CNAME.
Trailing dot confusion. Some DNS providers expect a trailing dot at the end of a target value (like tracking.esp-provider.com.) and some don't. If your provider adds a trailing dot automatically and you add one manually, you can end up with a doubled dot that breaks resolution. Check your provider's documentation on this one.
Subdomain already in use. Picking a subdomain that's already doing something else, like mail.yourdomain.com or links.yourdomain.com, creates a conflict. Choose a clean subdomain that isn't being used for anything else.
Testing too early. DNS changes don't go live instantly. Propagation can take anywhere from a few minutes to 48 hours depending on your TTL settings and DNS provider. If you check right after saving and see failure, you might just be looking at a cached response. Give it at least an hour before you start troubleshooting.
After setup, verify the record is resolving correctly with an external DNS lookup tool before you call it done. If you're stuck mid-setup and not sure what's wrong, our SOS hotline is free and we'll take a look with you.
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