Azure web service root domain works but not www subdomain

Question

I have an Azure web app to which I have mapped a custom domain from another registrar. The root domain works fine and is secured with a (free) Azure SSL cert. I have not been able to get the www. subdomain to work. (It is also secured with an Azure SSL cert.)

I have followed these three articles that detail the method to Map an existing custom DNS name to Azure App Service, Add a TLS/SSL certificate in Azure App Service, and Secure a custom DNS name with a TLS/SSL binding in Azure App Service.

When I browse to the example web app, astroguru.com, it displays a simple blazor server starter page as it should. If I browse to www.astroguru.com, I get a page not found with info icon in the address bar that says the site is not secure, as shown below:

Below are the DNS records that I have created exactly as described in the first article ref'd above, which include (and see image below):

• an A record pointing to the IP address of the web service.
• a TXT record containing the verification ID
• a CNAME record for the www subdomain that the tutorials say must point to the original site name (e.g. astroguru.azurewebsites.net)
• along with another TXT record with the hostname asuid.www and the same verification ID.

The image below shows the two secured URLs from the Azure portal.

The image below shows the two private key certs in the Azure portal that secure the two URLs above:

Can someone tell me what I've done wrong here?

Answer 1

Had to recreate the certificate and rebind.