"Sponsored email" on ATT mail causing retr cannot get msg. Cannot get any male in TBird .Cannot delete in web client. No select box, no date. Opens ad sites.
Then only place I see the email is in the att web client. It did not get through or cause any problems with Android mail, apple mail on mac or ipad. Just stops Tbird from downloading any mail fro this email account. RETR... cannot get message. Cannot delete in web client. cannot highlight, drag to trash or select in any way. Seems to be a yahoo thing. basically, I cannot use tbird on this account because of this POS email or whatever it is. Select box is a pretty little ad for AMEX, and other legitimate biz... changes each time I open it in web client. Takes me directly to the evil advertisers what would condone and be part of thisgarbage.
Wšykne wótegrona (3)
You problem only occurs with pop mail. I would be your other devices are using IMAP as it synchronizes mail with the server.
This issue can only occur in pop mail account where Thunderbird is instructed to leave messages on the server. ATT appear to reindex the mail on the server with monotonos regularly as we see their customers here all the time with this issue.
What is happening is the mail ATT tells Thunderbird is on the server has one number today and another tomorrow, to the RETR error occurs.
On the toolbar 
> Help> Troubleshooting information
Click on the Open Folder button.
Close down Thunderbird
In the explorer windows open the mail folder, then the ATT one. delete the file popstate.dat.
Restart Thunderbird. All your mail on the server will not download again. So you might want to install the remove duplicate messages add on https://addons.mozilla.org/en-US/thunderbird/addon/remove-duplicate-messages/?src=search
Thanks Matt. I went though the entire process (about 9000 emails reloaded). When it gets to the "bad" email, I still get the RETR error.
gstackho said
Thanks Matt. I went though the entire process (about 9000 emails reloaded). When it gets to the "bad" email, I still get the RETR error.
then you have a corrupt email in your inbox at ATT. having just seen them all download you will have a fairly good idea of the date of the message. Log into the ATT web mail and delete likely candidates unto the problem goes away. As spam is often malformed, start by deleting stuff in the ATT spam folder.