Fixed – AADSTS7000218: The request body must contain the following parameter: ‘client_assertion’ or ‘client_secret

While trying to access Azure resources using UsernamePasswordCredential credential we were getting the below error

https://docs.microsoft.com/en-us/dotnet/api/azure.identity.usernamepasswordcredential?view=azure-dotnet

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.

https://docs.microsoft.com/en-gb/azure/active-directory/develop/scenario-desktop-acquire-token?tabs=dotnet#username-and-password

More on ROPC

https://nishantrana.me/2019/08/23/connect-to-dynamics-365-web-api-using-oauth-2-0-resource-owner-password-credential-ropc/

Hope it helps..