can't send message via account IMPA has a red dot against it? help

Hi i'm sending messages via my google account and it isn't working - now the password is correct but it keeps coming up with IMPA in the correction doctor and well i have no idea, why this has happened and how to resolve it as its been working fine. HELP as its really frustrating as i have to go to the account provider (google) to do any of my work now. Ps i seem to be getting incoming mail but cant send. Thanks