Domain problems

Start from what you are seeing. Several of these are the product working as designed rather than a fault.

#In this section

Custom domain is stuck on "Validating…"My custom domain is stuck on "Validating…".Adding a domain fails with "Domain is already in use on another CloudFront distribution"Adding a domain fails with "Domain is already in use on another CloudFront distribution".Deleted a site and now I cannot re-add its custom domain to the replacement — it says "Domain is alrI deleted a site and now I cannot re-add its custom domain to the replacement, it says "Domain is already registered".Apex domain (example.com) will not workMy apex domain (example.com) will not work.Adding a domain is refused with "Safety check unavailable"Adding a domain is refused with "Safety check unavailable".Legitimate company domain was blocked as brand impersonationMy legitimate company domain was blocked as brand impersonation.

Troubleshooting

Every symptom.

Limits and quotas

When you hit a cap.

Update and promote

How publishing works.

Most of these are expected behaviour.