Test Manager Integration with Azure DevOps is not working - Getting error "Provided personal access token is not valid"

Hi, I’m trying to integrate Azure DevOps with Test Manager. The Azure DevOps URL for my project follows the pattern: https://{organization}.visualstudio.com

In the Test Manager-> Integrations->Azure DevOps, I have provided the connection details.

ServerUrl: https://{organization}.visualstudio.com
Personal Access Token: Generated token from Azure DevOps using Custom Defined Scope since my organisation has disabled Full access scope when creating Personal Access Token.

When I click on Create getting error as “Provided Personal Access token is not valid”. The question is whether the ServerUrl which I’m providing is correct format? also can we use token generated by Custom defined access scope

We are facing a similar issue in that full access PATs are disabled for the organization. Is there some documentation on why the full access scope might be needed? Otherwise we cannot request an exception from IT.