I am attempting to transfer an existing domain to Azure Front Door, following the instructions here: https://docs.microsoft.com/en-us/azure/frontdoor/front-door-custom-domain#map-the-temporary-afdverify-subdomain
Per the instructions on mapping a temporary afdverify subdomain, I added a cname entry for the existing domain (xyz.contoso.com) as follows:
afdverify.xyz.contoso.com -> afdverify.contoso-frontend.azurefd.net
Once that change propagated, again following the instructions, I went to the front door designer to add my custom domain as a frontend host. Here's where I run into trouble. I do not understand step 5:
For Custom hostname, enter your custom domain, including the subdomain, to use as the source domain of your CNAME record. For example, www.contoso.com or cdn.contoso.com. Don't use the afdverify subdomain name.
What subdomain do they mean here, if it's not the afdverify one?
If I enter afdverify.xyz.contoso.com, I get an error that it can't find a CNAME record for that domain that points to my frontdoor (contoso-frontend.azurefd.net).
If I enter xyz.contoso.com, it lets me add the custom domain, but when I try to save I get an error that "Another custom domain with the same host name already exists."
I do not have xyz.contoso.com registered with any other app -- it is pointed to Azure Traffic Manager in the domain record.
If I try to hit afdverify.xyz.contoso.com directly in the browser, I get the "Our services aren't available right now" error -- which implies it's hitting my front door instance, but doesn't help me actually verify that my custom domain is working as expected.
What am I missing here? How am I supposed to verify my temporary subdomain so that I can confirm it's working and move on to migrating the actual domain?
Any advice appreciated. Thanks.