Hi Support, "Sending of the message failed. An error occurred while sending mail. The mail server responded: Error sending message for delivery.. Please check the message and try again." v91.9.1 (32-bit) I've been getting this msg for the last couple of weeks. It doesn't tell me what's wrong & I can't figure out what's wrong. I haven't changed anything, but I think there was a recent update of Thunderbird when I was opening it one day. I checked the options, nothing looks corrupted. Any suggestions? The error msg is really not that helpful. I detest using Yahoo, so any help would be appreciated. Gratefully, Eileen