For several days now, I can send but not receive email messages via Thunderbird (although I do receive messages through my webmail and on a tablet and phone that don't use Tbird). Here's the error message: "The DELE command did not succeed. Error marking a message as deleted. Mail server mail.mydomain.com responded: already deleted." I've tried the few suggested fixes I've found online (checked my account settings, reset my password, deleted the first and last messages in my webmail inbox) but that's gotten me nowhere. I have no idea what message or messages the DELE command is trying unsuccessfully to delete, or why my domain server is saying "already deleted." Does this indicate a corrupted message somewhere? In which case, can I find it in my webmail inbox and try to do away with it? Or...well...what's going on? Any ideas?