Screenshot by Don Reisinger/CNET

Customers who use AT&T as their Internet service provider are unable to connect to Xbox Live, Microsoft's director of programming for Xbox Live, Larry Hryb (better known as "Major Nelson"), announced on his Twitter account today.

"If AT&T is your ISP, you may have problems connecting to [Xbox] LIVE," Major Nelson wrote. "We're working to resolve."

Following that tweet, CNET received word from an AT&T customer confirming Nelson's claim. The person said that they are unable to "sign on [to Live] via Xbox or to any Xbox domain," including Xbox.com and Microsoft's Xbox support page.

Although some folks are apparently having issues, Xbox Live's status page shows the online service, which allows users to play games and download digital content, is "up and running," indicating it's not a widespread problem.

In May, the Xbox Live Marketplace and Games for Windows Marketplace went down due to "an internal operational error." The service was restored the same day.

Neither Microsoft nor AT&T immediately responded to a request for comment.