Fastly Error: Unknown Domain

How to fix it

Try these in order — the most common fix is first.

1. 1. Add the domain and activate

   Copy steps
   1. Log in to the Fastly control panel and open the service
   2. Click Clone to edit, then Domains, and add the exact hostname
   3. Activate the new version on Production
   4. Reload the site after a minute
   Did this fix it? Yes No

2. 2. Test before switching DNS

   Copy steps
   1. Look up a Fastly POP IP with dig on your domain or dualstack.nonssl.global.fastly.net
   2. Add a temporary hosts file entry for the domain, for example 151.101.0.204 www.example.com
   3. Open the site, then remove the hosts entry once the real CNAME points to Fastly
   Did this fix it? Yes No

3. 3. Check the CNAME value

   Copy steps
   1. In Domains, click View/edit and copy the CNAME under DNS details
   2. Run dig www.example.com +short and confirm it returns a Fastly hostname
   3. Use a subdomain such as www: CNAME records cannot be used on an apex domain
   4. If you use a wildcard CNAME, add the matching domains to the service too
   Did this fix it? Yes No

Symptoms

Browser shows a Fastly error page saying unknown domain for your hostname.

Why it happens

• The CNAME was switched to Fastly before the domain was added to a service
• The domain was added to a service version that is not activated
• The hostname in the request differs from the domain added (for example www vs apex, or a missing wildcard domain)
• The service was deactivated or deleted but the CNAME still points to Fastly

This guide also covers

• fastly error unknown domain
• fastly unknown domain
• fastly error: unknown domain

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• Fastly Serves Wrong Content or Denies Requests From Origin (Override Host)
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