While trying to access Azure resources using UsernamePasswordCredential credential we were getting the below error
Azure.Identity.AuthenticationFailedException: ‘UsernamePasswordCredential authentication failed: A configuration issue is preventing authentication – check the error message from the server for details.You can modify the configuration in the application registration portal. See https://aka.ms/msal-net-invalid-client for details. Original exception: AADSTS7000218: The request body must contain the following parameter: ‘client_assertion’ or ‘client_secret’.
Trace ID: ef6c9e2b-862a-4a8b-9519-9a9072d23301
Correlation ID: 5f9bae95-e45a-4da5-b27c-ad9704e7334e
Timestamp: 2020-11-28 05:58:05Z’
This was because Allow public client flows was disabled for the application registered in Azure AD.
Enabling it fixed the issues for us.
More on ROPC
Hope it helps..