The problem was spotted earlier this morning by News.com readers in the San Francisco Bay Area. An AOL representative said that some users from the New York area also notified the company of the problem.
AOL was unable to provide more details about the locations affected.
AIM's network handles as many as 1 million simultaneous users during peak usage periods, although the representative would not estimate the number of users affected today. "Since every day the peak simultaneous users and logins fluctuate, that's a hard number to quantify," the representative said, adding that the network problems were resolved this afternoon.
AIM is a software client that non-AOL subscribers can download for free. The software has become extremely popular among Web users and AOL members, but AOL has had numerous run-ins with software giant Microsoft, which produces a similar product called MSN Messenger Service.
During the summer the companies engaged in a battle when Microsoft allowed MSN Messenger users to communicate with AIM users. AOL criticized the move as a hack and blocked Microsoft from accessing its users.