Email problem with xDSL connection

having problem accessing the email account (bellsouth) of one of our users. recently switch to xDSL service (2C2) but AOL, other different email account works fine. using internet connection sharing win98se. called bellsouth but they might be an IP problem specific to our xDSL provider (2C2). just wondering when i send a message to myself using the bellsouth accout it works. but sending email to other people doesn’t work
thx for answering