"Couldn't sign in" from Gmail App on Android

"Couldn't sign in" from Gmail App on Android

Hi,

since about 2 weeks, I keep getting the message that the Gmail app (which is also a generic IMAP client) can't sign in. The credentials are correct since it does retrieve emails occasionally with the same settings.

The app is configured to fetch emails every 15 minutes, but I keep getting that message every few minutes.

Greetins,
David