Hi, i'm using Thunderbird 91.3.2 (64-Bit) on Windows 10 and was quite happy up to last Monday (15.11.21). Since then i can't send Mails anymore. When i create a new Mail the send button is un-greyed as soon as i enter a valid reveicer address. But when i click on "Send", nothing happens. The mail-window stays open, no error message, no other reaction. To narrow down the arrow i deleted an SMTP server (not used anymore) and created a new one (server of a friend of mine, so i know for sure it's reachable and all data is correct). In the compose mail window i still see the old (deleted) SMPT server and the new one is not there. In the SMTP server setting window under "accounts" the list is correct (old one removed, new one is there). So somehow the server settings seem to not get refreshed or anything. Receiving mail works without any problems. I'm not using a proxy, firewall or anything else that could mess with my connection, but i also think the problem is not with the connection. Things i have tried already and that did not help: Run Thunderbird with Administrator rights. Try to update thunderbird (the "about" menu states that i have the most recent version). Restart in safe mode. Copy my profile folder and load that copy. The only plugin i have installed is "provider for google calendar". One more error I get, that might be related: When i reply to a mail the "send" button stays greyed out until i clear the whole receiver input field and enter a new addres (can be the same as the one i deleted immideatly before). After that the button is un-greyed but clicking on it has no effect, just as with a newly created mail. Is that a known bug, what additional information should i provide and what can i do against it? I'm using a german version of Thunderbird so please excuse if some of the buttons or menues are named differently than i tried to describe here.