I have called and chatted with AT&T several times (well over 4 hours now) about this problem.  It would seem something happened earlier this week or last with the way ATT connects with the Yahoo backend system for email authentication. When I try logging in from the Yahoo!mail page I get the endless

Hey folks, new to the forums, LONG time customer (15 years if you consider the previous ownership), and owner of (at one point) four different lines (now down to two). Apologies in advance that this is going to require some reading. Skip to the bottom for the TL;DR version, unless you are an actual