“Checking inbox for new messages” appears for several minutes then “No messages to download” appears on my Windows computer with AT&T POP Server. Messages exist, my cell picks them up. Had problem for weeks. Reinstalled Thunderbird. Computer downloads messages periodically. Older error message was "The account xxx email is being processed. Please wait until processing is complete to get messages." AT&T says it is not their problem, but Thunderbird. Help. Should I install the Beta Thunderbird or use an IMAP server or what else can I try. I have all my old emails in folders so changing mailers would be problematic. Help Thanks