For the past few weeks, off and on Thunderbird will not send/receive email and this message (in question line) shows up: Sending of password for user (my email address) did not succeed. Mail server inbound.att.net responded: Server Error - Please try again later. A couple of days ago AT&T had me reset the password on Att.net (their webmail with Yahoo which works). When I did that, Mozilla Thunderbird still did not work nor did the MAIL app on my I phone. I reset the password a second time and then all three worked (Mail App, Thunderbird on laptop, and webmail, which I never use). It was stable for about 24 hrs then the same problem recurred. Once again, Thunderbird will not work. I have used it for several years in lieu of Outlook. I am not going to reset the password every other day so I am looking for a solution. Thunderbird finds the AT&T pop and smtp servers automatically.