Can't send emails
Running TB 115.7.0 on an iMac. I've made no changes to any of the setting recently. Overnight it stopped being able to send messages. Instead I get this error message:
"Sending of the message failed. An error occurred while sending mail. The mail server responded: Requested action not taken: mailbox unavailable Sender address is not allowed.. Please verify that your email address is correct in your account settings and try again."
I have checked my email address in account settings and I have checked my SMTP settings and all seems to be correct. What could have caused this sudden change in TB's behavior and what can I do to fix it?
Thanks, Ted