Thank you for reaching out.
Can you please confirm if you have added the custom domain on the Azure Front Door aswell?
If yes, as documented here
When you add a domain to your Azure Front Door profile, you configure two records in your DNS server:
- A DNS TXT record, which is required to validate ownership of your domain name. For more information on the DNS TXT records, see Domain validation.
- A DNS CNAME record, which controls the flow of internet traffic to Azure Front Door.
Can you please confirm if you have added CNAME record?
Meanwhile as documented here
If your domain CNAME is indirectly pointed to an Azure Front Door endpoint, for example, by using Azure Traffic Manager for multi-CDN failover, the DNS state column shows as CNAME/Alias record currently not detected. Azure Front Door can't guarantee 100% detection of the CNAME record in this case. If you configured an Azure Front Door endpoint to Traffic Manager and still see this message, it doesn't mean that you didn't set up correctly. No further action is necessary from your side.
Thank you!