The problem may be your antivirus (software firewall) or the proton bridge software.

Thank you, Matt. I discovered my former proton bridge software was corrupted and started over with a new download. I could not find issues with my antivirus. My email is still not working.

The issue is the bridge uses the localhost adapter 127.0.0.1 This is a long term vector for spyware, malware and SPAM bots. While locally hosted spam bots are not the issue they were in the past the semi paranoid way antivirus products managed this location in the past has not changed. So often the issue if the antivirus/ software firewall simply blocks the communication on the localhost. Hardware firewalls open and close ports and protocols on those ports. The issue with software firewalls is they tend to use software names and version numbers to allow traffic, so any change is either can see what was functional just stop without notice or a clue to the cause. So your Thunderbird version changing or your bridge software updating could either be enough to tip this rather delicately balanced house of cards on it's head. So you are not looking for something "wrong" with your antivirus product, you are looking for something doing exactly what it was set up to do. Just very inconveniently. It is for this reason I am always suggesting these two following actions as they shed light on what the issue may be simply be excluding a lots of what has become "normal" dross of computing, but is also a common cause of mystery issues. Please try them and see if things work in that state. Note that you would will need to manually start the bridge in the OS safe mode test before Thunderbird.; * Does Thunderbird work as expected in [[Troubleshoot Mode Thunderbird|Thunderbird troubleshooting mode]]? * Does Thunderbird work as expected with your OS started in '''[http://en.wikipedia.org/wiki/Safe_mode safe mode with Networking]'''. Instructions for each operating system: [https://support.microsoft.com/en-us/windows/start-your-pc-in-safe-mode-in-windows-92c27cff-db89-8644-1ce4-b3e5e56fe234 Windows 10/11], [https://support.microsoft.com/en-us/windows/windows-startup-settings-including-safe-mode-7f31dcea-6427-0ba0-ec1b-729a56321cd3 Windows 8], [https://support.microsoft.com/en-us/windows/advanced-startup-options-including-safe-mode-b90e7808-80b5-a291-d4b8-1a1af602b617#start-computer-safe-mode=windows-7 Windows 7], [http://support.apple.com/kb/ht1564 OSX]