Discontinued: Less secure app access
Starting May 30, 2022, Google will no longer support the use of third-party apps or devices which ask you to sign in to your Google Account using only your username and password also known as "Less secure app access". This was the easiest way to use Gmail on 2N OS devices.
Solution: App passwords
We recommend you switch to "App passwords" way of logging in 2N OS devices to Gmail. An App password is a 16-digit passcode that gives a non-Google app or device permission to access your Google Account. It's very simple to set up and more secure compared to the discontinued "Less secure app access" option.