Could be. Also, what AV do you use?

Could be. Also, what AV do you use?

I've been using Huorong AV, VPN, and Thunderbird with network auto-detect, without any issues until last week. Recently, I’ve been facing frequent problems where Thunderbird can’t connect to my SiteGround mail server. It freezes when sending emails and when saving emails to the sent folder. I have around 2GB of emails, so I’m wondering if that’s related.

I spent a lot of time today: I uninstalled Thunderbird, deleted all related files, and then downloaded the latest ESR version (128.58.0esr x64) from the official website. After re-setup, I still faced freezing when recognizing email settings at first, but it eventually worked. I’m still using Huorong AV + VPN + Thunderbird (network auto-detect). Everything seems normal now, but I don’t understand what the issue was.

Anyone know why this happens? Also, any suggestions for antivirus software that can scan Thunderbird emails for viruses?

A VPN obscures the location of the local computer, which interferes with most mail authentication/verification processes. If you can't configure the VPN to allow TB connections, you will have to disable it while doing mail operations.

As well, you should exclude the TB profile folder from AV scanning, leaving the real-time background scan in place. This is recommended for all AV apps.