Failure to Send
About 75% of the times I try to send an email I get the following: "Sending of the message failed. The message could not be sent because the connection to Outgoing server… (read more)
About 75% of the times I try to send an email I get the following: "Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.XXX.XXX was lost in the middle of the transaction. Try again." Failure is more common with attachments, and gets worse with increasing attachment size. For one message with a 600K attachment, I had to try 44 times before the message went. The problem occurs on a desktop and two laptops that use Thunderbird. Opening Thunderbird in Safe Mode did not help. My ISP cannot find a problem and believes the problem is caused by Thunderbird. I think the problem started in October 2020.