401 Unauthorized error when sending POST request in Postman.

[HossameTor]

I have a problem when I try to send a POST request via Postman to test my POST methods. I am getting a 401 unauthorized error.
At first, I suspected that the 401 unauthorized error was caused by an authentication problem. However, when I tried a GET method that also required authentication, it worked fine, so the issue must be specific to the POST endpoint.