I set up a new email address. I'm getting this message and have no idea what it means: he STAT command did not succeed. Error getting message number and sizes. Mail server pop.gmail.com responded: [AUTH] Username and password not accepted.

      Incoming Mail (POP) Server: pop.gmail.com
     Requires SSL: Yes
     Port: 995

You can ignore the "STAT" part of the error - it's a technical alert - the actual problem, I believe, is that Google isn't authenticating you. A frequent problem is that they need to set a cookie during the initial OAuth2 authentication process, but you may have intentionally or accidentally disabled cookies. So, check these things: - Confirm you have the correct server settings. According to Google (https://support.google.com/mail/answer/7104828), they should be Incoming Mail (POP) Server: pop.gmail.com Requires SSL: Yes Port: 995 - Make sure you have chosen OAuth2 Authentication in both your POP3 and SMTP settings - Make sure cookies are allowed (<Settings | Privacy & Security | Web Content | Accept cookies from sites>); The next two steps may not be necessary, but they won't hurt... - Delete all cookies for that account (<Settings | Privacy & Security | Web Content | Show Cookies>); - Delete all passwords for that account from saved passwords (<Settings | Privacy & Security | Passwords | Saved Passwords>); Now restart Thunderbird. You will be asked for your credentials, an OAuth2 token will be set, and hopefully they will be accepted and mail retrieval will resume.