Credentials pop up box is inoperable -- eM Client and Thunderbird

Windows 7. I keep getting the credentials pop up box but the box buttons don’t work. I initially set up my custom email in Thunderbird and it was seamless. Got the box, box worked to connect my email with my password. Done. But last week I changed my password and now can no longer use my custom gmail in Thunderbird. I also tried deleting the account and redoing it, same results. I know Tbird has issues, but to avoid reinstalling it, I tried eM Client and got the same results.

I don’t know if this has anything to do with it, but I also activated 2-method authentication, but then deactivated it, set up new password a bunch of times, and also changed my password back to the original. Nothing. After doing all the things google said to do, I researched some about email clients and noticed they had Thunderbird listed as incompatible with google security. So I downloaded eM Client and I can get my mail and everything works and I have less secure set, but I never connected through the box because it doesn’t work with eM Client either. The inoperable box keeps popping up, I still can’t do anything with it, and I have to CLICK each time to get rid of it. I feel like if I can access the box properly, I can input my password and then all will be well with the universe. Please help me?