Thunderbird 102.6.1 (64-bit), Avast 22.12.6044 (build 22.12.7758.769), Win10 22H2
Unable to send email message from Thunderbird, unless I turn off “scan outgoing emails (SMTP)” or turn off Mail Shield in settings. Message then gets sent immediately.
I tried turning off the Avast signature from outgoing emails, but that had no effect.
I have been having this problem for some weeks, so is not a recent update.
EDIT:
Problem is peculiar to IMAP email account. I am receiving emails from that IMAP account, but avast mail shield is blocking sending emails.
Otherwise similar to this problem. https://forum.avast.com/index.php?topic=234536.0
I have tried this https://support.avast.com/en-ww/article/91/#pc
but Avast exported Certificate is already there in Thunderbird when I tried to import it.