Error sending mails following update to 78.4.0.
This morning Thunderbird was updated to 78.4.0. Incoming mails (POP3) work fine. But suddenly outgoing mails are rejected: "An error occurred while sending mail. The mail server responded 450 4.1.8 <my email>: Sender address rejected: Domain not found. Please check the message recipient ".... recipient ..." and try again.
Sending mails worked fine till update was installed, and I have not changed any SMTP settings. Same error for all recipients of mail.
Any suggestions?
الحل المُختار
Turned out to be a problem with the provider. Problem is solved.
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الحل المُختار
Turned out to be a problem with the provider. Problem is solved.