This error is presented when the reset email used does not match the last one sent from the server, or more than 24 hours have elapsed and the link has expired.
The password reset link has a 24 hours lifespan and sometimes if the "Forgot your password" button is pushed twice, then the first email is applied to the second reset. The result is predictably an Internal Server error.
Attempts to log in after that may then produce an Invalid Credentials error. This error says that the email, password or both do not match those stored on our servers.
To get out or this cycle of login errors, delete all previous emails and reset your password.