I just tested in a fully up-to-date 18.04 VM, I configured thunderbird to use a test gmail account and used enigmail to generate a new keypair. After that I was able to correctly send plain e-mails, e-mails with a signature, and encrypted e-mails.
Can you make sure you don't have another version of enigmail locally installed in your profile? What version number does the extension report? What is the output of `apt policy enigmail`? Can you copy-paste the contents of the developer console (which you can open in Thunderbird with Ctrl+Maj+J)? Thanks! ** Changed in: thunderbird (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1847735 Title: thunderbird can't send anymore (when enigmail is enabled) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/thunderbird/+bug/1847735/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs