My custom subdomain isn't working. How do I troubleshoot DNS issues?

Custom domain issues are usually DNS-related. Here's how to troubleshoot:

Check your DNS configuration:

1. Verify you created a CNAME record (not an A record) pointing to the value GitBook provided.

2. Ensure you're using the subdomain format (docs.yoursite.com or www.yoursite.com

3. If using Cloudflare, disable the orange cloud (proxy) - it must be set to "DNS only"

Common DNS issues:

• Conflicting records: Remove any existing A, AAAA, or other records for the same subdomain

• TTL delays: DNS changes can take up to 48 hours to propagate globally

• CAA records: If you have CAA records, add 0 issue "pki.goog" to allow GitBook's SSL certificates

Test your setup: Use a DNS lookup tool like WhatsMyDNS.net to verify your CNAME record is pointing to the correct GitBook address.

If you continue having issues after 48 hours, contact support with your domain name and the CNAME value GitBook provided.