@utzer @agowa338 Sorry for the delay - we have three steps to suggest. The first is troubleshoot mode, which you can access via Thunderbird Menu > Help. If that doesn't improve things, we suggest disabling third party software that might be interfering, like anti-virus and firewalls. If neither work, file your issue at support.mozilla.org/new with your OS, TB version, and any other information that can help troubleshoot this issue. We hope this helps!