Adding custom domain (in app service) as wildcard "*.domain.com" gives error 'provided record set relative name 'asuid.*' is invalid'

Question

Edit: I had to replace the * character with symbol ★ or else it is not displayed in the message.

When I try to add a custom domain (App Service) as a wildcard "★.sysdev.nl", the Azure Portal displays the error message:

Failed to assign custom domain ★.sysdev.nl on sysdev-appservice-website The domain name 'asuid.★.sysdev.nl' is invalid. The provided record set relative name 'asuid.★' is invalid.

I suspect that Azure Portal tries to add a CNAME record with hostname 'asuid.★' and that syntax is not allowed by the Azure DNS. The correct CNAME record is 'asuid' without the '.★' , that is what I read in the Azure documentation.

Maybe a bug in Azure Portal, because last week I was able to enter the wildcard domain without problems.

Thank you, Frank

Answer 1

The very same problem here also.