Please explain the problem in detail. What did you do step by step? What happens? What is/are the exact error message(s) ?

Some problems occur when your Internet security program was set to trust the previous version of Thunderbird, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow to connect to the Internet again;

• Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
• Remove Thunderbird from your program's list of trusted or recognized programs. For detailed instructions, see

Configure firewalls so that Firefox can access the Internet. {web link}

I click on my icon to open my email. It usually opens and loads any new messages. Now all it does the the far left upper corner where it says emails, there is this little dot just going back and forth. A week ago it did say "Thunderbird is not responding" When it does that It usually takes a few seconds to respond. Of course if it doesn't I check my internet. It has been a week since this started. I called my internet supplier. He check everything and said I'm good there that I should now get a hold of Thunderbird. Does this help. Most of the time I can figure this out. I will tell you I'm not a computer guru.

Thanks

Did you check the firewall?

Also, open Thunderbird. On the far right, click the 'hamburger' (3 horizontal lines) icon. Then File > Offline. Make sure you are not offline.