AADSTS7000218: The request body must contain the following parameter: client_assertion or client_secret

Issue

When using Username and Password authentication, you encounter the following error: "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."

Solution

1. In Azure, go to App registrations, select your application, then navigate to the Authentication tab.
2. Go to Advanced Settings and enable the Allow public client flow setting.