Hi there, If I write a new email or reply to one, I can't send it. Also "save draft" fails. It does not give any error messages, the window just does not close. If i close it tells me, that Thunderbird is currently saving the email or sending the email (in German, I run the German version), I can confirm and delete the email/draft or cancel and wait. I once waited for several hours, there is no end to this "saving/sending" of an email, even no error. I have this for several months now. First it just happened every now and then, after restart etc. I could write and send an email again. Also I could click "response/write email" and click very fast to save draft, then this worked and it did not break for that email. But now it does not work at all. For no account (private server, gMail, hostEurope, 1&1), so I assume it is not related to any server configurations, because it would hardly break for all at the same time. I have also deactivated all non-calendar related add-ons. Receiving is fine, by the way. Thunderbird 52.1.1 (64-Bit), Ubuntu 16.04 Any suggestions?