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-hour lifespan and if the "Forgot your password" button is tapped twice, then the first email is applied to the second reset, resulting in 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 of this cycle of login errors, delete all previous emails, and reset your password.
For more information see How do I reset my password when logged out?