What is "account_mismatch" error in /oauth/token response?

We are trying to use /oauth/token with grant_types password to verify username+password pair.

If the username or password is incorrect, /oauth/token will return “Email or password is incorrect”. This is nice.

But when the username and password are correct, /oauth/token now returns:

    "error": "unauthorized",
    "error_description": "account_mismatch"

Could someone help explain what is the meaning of above error? Thanks in advance.

Hello, this looks like an error that may be coming from a Rule you may have written. Rules are run after a successful authentication in the resource owner password flow. You can debug your rules with our real-time Webtask Logs extension which prints any console.log() statements.

Thank you sooooo much. We haven’t been touching Auth0’s code for almost half a year (indicating Auth0 works so well?), and have completely forgotten about Rules. That error indeed came from one of our Rule.