Every time I change providers, I have problems with my SMTP settings. I moved, had to change to AT&T. I got the recommended settings from AT&T, entered them for both incoming (POP) and outgoing (smtp.att.yahoo.com); port for incoming: 955; port for outgoing: 465; Connection security: SSL/TLS; authentication: no authentication & password (neither work). I called AT&T and they said everything is set correctly. I can RECEIVE messages, but can't SEND them. If I use AT&T's e-mail to send messages, it works - but T-bird still doesn't work. What am I missing?