Google has updated their GSUITE API and no longer support basic authentication (username + password).
It means that clients that has configured GSUITE connection in the agent will no longer be able to connect to it.
All clients must generate ‘APP PASSWORD’ and use it instead of their account password.
The agent UI is already updated.
More details can be found here: Sign in with App Passwords - Gmail Help (google.com) (this link is also in the agent UI)
The relevant part is this:
Please provide instructions for API setup