Unable to map custom domain name to CDN endpoint

Question

Hi there, I created a DNS zone for a subdomain comms.XXXXXX.com and added those NS records to the root domain I have in AWS. I want this subdomain to be mapped to CDN endpoint. I created a CNAME record set (ui.comms.XXXXXX.com) to points to my CDN endpoint resource created in the different resource group. But while mapping the custom domain name, I get the following error:

DNS zone records:

I even tried to add CNAME records with No alias set and directly pointed to my CDN endpoint. This worked for me last time but still getting the same error while mapping the domain name.

I even waited for 5 days if there is any propagation issue but still, I couldn't able to map the custom domain name. I don't know the proper way to check CNAME but I checked with https://dnschecker.org/ if the CNAME is propagated. I could see the CDN endpoint.

Answer 1

The way CDN looks up and validates DNS is changed recently. If you have abc.xyz.xxxxx.com, CDN looks for ns records of xxxxx.com and then ns record for xyz.xxxxx.com and then ns records of abc.xyz.xxxxx.com. In this case, it will work fine.

But if you have TLD xxxxx.com and created a subdomain abc.xyz.xxxxx.com and added it CNAME to TLD xxxxx.com, the validation is failing since there is no ns record for xyz.xxxxx.com. This worked well before but fails now. We raised it to support and the team is working on it.

So the solution for now is, either you need to create a subdomain for each level or have to change the format as we did abc-xyz.xxxxx.com