I use SBC Dial or DSL and cannot send email from my POP client. What happened?
AT&T and its partners have implemented a program aimed at combating unsolicited commercial email (spam). AT&T now filters port 25, which means that many of its users are now required to send email through AT&T's own SMTP servers. If you use AT&T to gain access to the Internet (via a dial-up or DSL connection) and have purchased a Yahoo Small Business plan that includes email, you will likely need to replace the Yahoo SMTP server address in your POP settings with an SMTP server address specified by AT&T. See the list of settings.
For more information about AT&T's SMTP requirements, please visit the AT&T help center or contact AT&T DSL support at 877-SBC-DSL5 (877-722-3755) or AT&T DIAL support at 866-SBC-DIAL (866-722-3425).