Catch invalid_grant error and explain how to clear tokens

[metalwarrior665]

This error means we used expired tokens. But it can also mean other things: https://blog.timekit.io/google-oauth-invalid-grant-nightmare-and-how-to-fix-it-9f4efaf1da35

https://apifier-circular-logs-prod.s3.amazonaws.com/szTzSfgWmjS8PwCpH.log.gz?AWSAccessKeyId=AKIAJTQHBVH6QKNNBOIQ&Expires=1588150215&Signature=JQQMuGvohXZVOOQnczxFFeaO%2B5s%3D&response-content-disposition=inline%3B%20filename%3D%22szTzSfgWmjS8PwCpH.log%22

[metalwarrior665]

Important note: The tokens get revoked when changing passwords. So I need to explain this in the log/docs as well.