How to Fix Email Links That Don't Open in Sparkforge

By Sparkforge Support Team ·Last reviewed May 3, 2026

When Sparkforge emails open to "This site can't be reached," the Mailgun tracking subdomain (email.mg.yourdomain.com) isn't resolving. Verify the CNAME points to mailgun.org, check the tracking protocol in Mailgun, and confirm your DNS provider didn't append the root domain to the host name.

Sparkforge rewrites every link in your outbound email to route through your Mailgun tracking subdomain — something like email.mg.yourdomain.com. That's how open and click tracking works. If the CNAME for that subdomain isn't set up correctly, the rewritten link fails with "This site can't be reached / refused to connect."

The fix in three steps

Identify your tracking subdomain.
Verify the CNAME resolves to mailgun.org.
If DNS is fine, fix the tracking protocol in Mailgun.

Step 1: Identify your tracking subdomain

The Mailgun subdomain you set up determines the tracking host. Sparkforge prepends email. to it:

If your Mailgun subdomain is mg.companyname.com, the tracking CNAME is email.mg.companyname.com.
If it's replies.companyname.com, the CNAME is email.replies.companyname.com.
If it's support.companyname.com, the CNAME is email.support.companyname.com.

Step 2: Verify the CNAME

Open MX Toolbox or WhatsMyDNS.
Look up the CNAME record for your tracking host (e.g., email.mg.companyname.com).
It should resolve to mailgun.org.

If the lookup says "DNS records not found"

Log into your domain registrar's DNS panel.
Add the CNAME with host email.mg (or email.replies, email.support — match your subdomain) and value mailgun.org.
Wait for propagation (typically 5–60 minutes) and re-test.

Step 3: Fix the tracking protocol

If the CNAME already points to mailgun.org but links still fail:

Open Mailgun and go to Sending → Domain Settings.
Edit the Tracking Protocol (toggle between HTTP and HTTPS — enable HTTPS tracking links).
Send a test email from Sparkforge and click the link.

Common DNS pitfalls

Root domain appended to the host: GoDaddy and Namecheap auto-append the root domain. The host name should be just email.mg, not email.mg.companyname.com. If you enter the full FQDN, you end up with a record for email.mg.companyname.com.companyname.com.
TTL too high: if you fixed the record, propagation can lag. Lower the TTL temporarily to 300 seconds for faster updates.

If the registrar verified the records are correct and links still fail, escalate to support with the test email message ID.

Frequently Asked Questions

Why do email links go through email.mg.yourdomain.com instead of the original URL?

Sparkforge rewrites every outbound link to track opens, clicks, and unsubscribes. The rewrite uses your Mailgun tracking subdomain, which is where the CNAME has to resolve.

What CNAME value should email.mg.yourdomain.com point to?

mailgun.org. Set the host to email.mg (or email.replies / email.support, matching your Mailgun subdomain) and the value to mailgun.org.

Why does the host show as email.mg.companyname.com.companyname.com?

Your registrar appended the root domain when you entered the FQDN. Re-create the record with the host as just email.mg, no domain suffix.

How long does DNS propagation take?

Usually 5–60 minutes for a new CNAME. If the record was edited recently with a high TTL, give it up to 24 hours.