I used Thunderbird email software for more than a decade now, and never had an issue with receiving emails from Gmail.

In the summer of 2019 I started to get this error: “connection to server pop.gmail.com was reset”.

I use Windows 10 and the latest version of Thunderbird, which now it’s 60.9.0. I also use AVG Free Antivirus, current version 19.8.3108.

These are the solution that worked for me.

The last solution is a definitive solution.

1. Deactivate Email Shield in AVG.

I searched Google for a solution and I arrived on some forums that related the error to a conflict with AVG antivirus.

It was suggested to deactivate the Email Shield under “Web & Email” basic protection, which solved the problem temporary.

I also noted, that I reactivated the Email Shield and restarted to computer, the issue was also solved.

But if you shutdown the computer, when you start it again, the issue reappears.<...