Mail cannot login to Gmail: "Error 401: disabled_client"

A year ago, I started using “Mail” (instead of K9-mail) because it seemed like it was able to login to Gmail, as opposed to K9-mail.

But recently I started getting this error when trying to log in: “Error 401: disabled_client”.

Is that something I’m missing on my end, or could it be related to an update of Mail?

/e/'s Mail is a fork of K9. Both are capable of logging in to Gmail accounts, but Google have changed how you login, so you have to jump through a couple more hoops, whether using Mail of K9

Oh, got it!

I had to go to:

Mail > Settings > [the account] > Fetching mail > Incoming server

Then set the “Authentication” to “Normal password”, and then enter the “App Password” I got from Google into the “Password” field.

Somehow I was trying to log through the Google OAuth with the App password and that was not working.

Thanks for the help!

None of what was said here works. “App Passwords” require 2-step-verification. You can’t just turn it on for the purpose of resolving this issue because this will break account access from the other devices that were previously not using 2-step-verification. The same account cannot be accessed differently by different devices. Even if the account is already using 2-step-verification how will you get past the google sign in? The steps given for changing the authentication do not work because you cannot reach this setting if you enter a gmail address - it automatically goes to google sign in. This K9 mail variant is broken.

Well it works for me…