How to fix "CNAME/alias record is not currently detected" with non-Azure hosted custom domains

Tom MAILLARD 0

Hello,

I'm currenty experimenting with AFD and when I tried to register a custom subdomain on it, I've reached an issue where I correctly registered a domain, placed a CNAME record on my registrar (OVH), pointing towards the endpoint of my AFD. The CNAME looks like that : subdomain IN CNAME defaultendpoint.z03.azurefd.net.

Yet it appears that the record hasn't been taken into account by AFD, while it propagated successfully on third party sites / nslookup. User's image

Also when I try to access it using the custom domain, I reach a page not found page
User's image

I also have a reported error on a backend according to health events but I've been able to access my content just fine using the default endpoint, so I'm pretty clueless about what it means at this point User's image

If anyone has any clues or tips with AFD, it'd be very appreciated

Thanks a lot for your time

Silvia Wibowo 3,086 Reputation points Microsoft Employee

2024-01-08T03:02:30.4933333+00:00
Hi @Tom MAILLARD , I understand that you've setup custom domain for your Front Door profile. Certificate is installed, domain name validation is done. Nslookup returns the correct answer. You can access default Front Door endpoint (something like myendpoint-mdjf2jfgjf82mnzx.z01.azurefd.net). However, you still have 2 issues:

Accessing custom domain using web browser still says "Page not found".

Your Front Door DNS state is "CNAME/Alias record currently is not detected".

The second issue is not important. This document says (note at step #4): If your domain CNAME is indirectly pointed to a Front Door endpoint, for example, 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've configured an Azure Front Door endpoint to Azure Traffic Manager and still see this message, it doesn’t mean you didn't set up correctly, therefore further no action is necessary from your side.

First issue is important. As you've confirmed that nslookup returns correct answer, it should be able to load the Front Door page as if you're accessing default Front Door endpoint (not custom domain). Front Door configuration does take a while, sometimes up to 30 minutes, to propagate to different endpoint.

Could you please try accessing custom domain again from a browser? If it's possible, use multiple devices such as laptop, mobile phone, virtual desktop, or different browsers to narrow down the issue, whether it's browser, network, device, or Front Door configuration.
GitaraniSharma-MSFT 47,696 Reputation points Microsoft Employee

2024-01-09T13:04:31.1066667+00:00

Hello @Tom MAILLARD ,

Welcome to Microsoft Q&A Platform. Thank you for reaching out & hope you are doing well.

I understand that you've deployed an Azure Front Door and added a custom domain on it but are unable to access your application on the custom domain. However, the application works on the default endpoint.

I would request you to check if the route is mapped to the newly added custom domain.

A routing rule should be added for the custom domain to direct traffic to the selected origin group.

Refer: https://learn.microsoft.com/en-us/azure/frontdoor/troubleshoot-issues#requests-sent-to-the-custom-domain-return-a-400-status-code

Regards,

Gita
GitaraniSharma-MSFT 47,696 Reputation points Microsoft Employee

2024-01-10T12:41:57.2033333+00:00

@Tom MAILLARD , could you please provide an update on this post?
GitaraniSharma-MSFT 47,696 Reputation points Microsoft Employee

2024-02-01T12:45:04.4566667+00:00

@Tom MAILLARD , do you have any updates on this issue?