What could be the issue if my Webflow site with SSL enabled is showing a "Fastly error: unknown domain" message, even though the www domain is correctly registered in the hosting tab?
TL;DR
- Ensure both root and www domains are added in Webflow and set www as the default domain.
- Verify DNS records: CNAME for www to proxy-ssl.webflow.com and A records for root to 75.2.70.75 and 99.83.190.102.
- Enable SSL in Hosting settings and re-publish the site after changes.
- Allow up to 48 hours for DNS propagation and ensure third-party services like Cloudflare are set to DNS-only or compatible with Webflow.
The “Fastly error: unknown domain” with SSL enabled on a Webflow site typically means there is a DNS misconfiguration or missing domain setup. Even if the domain appears in the Webflow Hosting tab, Fastly (Webflow’s CDN provider) won’t serve the site unless everything is configured correctly.
1. Check That Both Root and WWW Versions Are Added to Webflow
- Go to Project Settings > Hosting.
- Make sure both the root domain (example.com) and www subdomain (www.example.com) are listed.
- If only one is listed, add the missing version and then publish the site to both domains.
2. Ensure Correct Default Domain is Set
- In the Hosting tab, make sure “www.example.com” is set as the default domain (the one Webflow recommends).
- Click “Make default” if it isn’t already, especially when using SSL.
3. Verify DNS Records Are Correct
- For www.example.com: Set up a CNAME record pointing to proxy-ssl.webflow.com.
- For example.com (root domain): Set up A records pointing to:
- (a) 75.2.70.75
- (b) 99.83.190.102
- Do not use a CNAME for the root domain—only A records.
4. SSL Must Be Enabled
- Go to Project Settings > Hosting and confirm SSL is toggled on.
- If it wasn't enabled previously and you just turned it on, re-publish your site to refresh the DNS propagation through Fastly.
5. Allow Time for DNS Propagation
- After making any changes, DNS can take up to 24–48 hours to propagate.
- Use tools like https://www.whatsmydns.net/ to check if your DNS records have fully propagated worldwide.
6. Cloudflare or Third-Party Services
- If you are using Cloudflare or a custom CDN, make sure it's set to DNS-only (gray cloud) or that SSL settings are compatible with Webflow.
- Avoid conflicting SSL or proxy setups that might block Fastly from handling the domain properly.
Summary
The "Fastly error: unknown domain" usually occurs when Webflow isn't recognizing your custom domain due to missing domain setup, incorrect DNS records, or SSL misconfiguration. Ensure both www and root domains are added in Webflow, the DNS is properly pointed to Webflow, and SSL is enabled and published.