Okay, Here are the basics: - change your security authorization to Oauth2 (do this for the incoming server settings and also for the Outgoing (SMTP) server - two places - remove the password entries for the account (remove the entire entries both incoming and outgoing) - that password info is at Tools>Preferences>Privacy&Security - click 'saved passwords' Then click 'show passwords' then highlight the rows with incoming and outgoing gmail servers and click DELete. - check to ensure that TB is set to accept cookies (that setting is just above the Passwords section) - Google will then step you through the authentication process for your PC. OR... If this is your one account, you might prefer to uninstall and reinstall and on the prompt for email, enter the gmail information but WITHOUT your password.