Maybe if you post a screenshot of the Google popup it may help. My 'guess' is that this is the one-time popup that Google does to confirm that you want to use Thunderbird as your agent for Gmail. Click 'allow' and it never comes back. That is a security feature that Google administers.

Hello David and thank you for your assistance. I tried to go to Thunderbird after logging onto the Google sign up page but it would not load. I also tried to log on and say allow but it would not load. Here are the first two screenshots of right as the box comes up and then a second later the sign up. The third screenshot is it telling me it cannot complete the task. Thank you again ...just as I was typing this, that Google sign up page popped up. It seems to pop up every few minutes. Also, I just learned how to copy a screenshot so that is something good out of all this.

Ok.try this: - in setting>privacy&security, check that cookies are accepted. If it had been previously unchecked, see if that fixes the problem. - if not, in privacy&security, click savedpasswords, then showpasswords, then highlight the account's rows and delete them and try again. than may require closing and restarting thunderbird.