Using Mender APIs result in 404 Not Found errors

Hello,

I’ve tried to follow the instructions on how to use the Mender API from this site: Using the APIs | Mender documentation

After I’ve set my environment variables and run the following command:

curl -X POST -u $MENDER_SERVER_USER $MENDER_SERVER_URI/api/management/v1/useradm/auth/login

I always get the following response:

Enter host password for user '*******':
{"error": {"status_code": 404,"message": "Not Found"}}[

Can somebody tell me why I always receive this error message?