I'm trying to use the script here (https://azure.github.io/AppService/2021/03/02/asmc-apex-domain.html) and modify it so that I can use it with subdomains as custom hostnames, using a CNAME record. It of course fails because it is looking for an A record for the apex domain.
I'm not sure what needs to be changed but my guess is ""domainValidationMethod":"http-token"". I don't know what the other methods available are, doc doesn't list them here https://docs.microsoft.com/en-us/azure/templates/microsoft.web/certificates?tabs=json.