Failed to create Free App Service Managed Cert

Niharika Koneru 441 Reputation points Microsoft Employee

Free managed app service cert creation/generation failing with below CNAME error:

Error: Failed to create App Service Managed Certificate for hostname Click here for more details. Error Details: Properties.CanonicalName is invalid. Current CNAME records of the hostname are,,

I was able to repro and make it work if my CName mapping is via subdomain to my default *

However, the issue seems to be appearing when my CName points to another subdomain before the default * as seen in error message below:


Any insights on this issue is appreciated?

Azure App Service
Azure App Service
Azure App Service is a service used to create and deploy scalable, mission-critical web apps.
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Accepted answer
  1. SnehaAgrawal-MSFT 18,286 Reputation points

    Thanks for asking question! You are seeing this behavior as it’s not a supported feature in Azure App Services yet. While generating managed free certificated azure will run certain checks on domain and looks for a valid CName ie, either pointed to “” or “” In order to solve this problem please follow below steps in order:

    Remove Cname (, make sure there is only one Cname which is pointed to either “” or “”

    Now attempt to generate the Certificate and bind it to domain.

    If you still want the after cert generation, you can read the Cname.

    Thank you to Naga sandeep for the assistance.

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