AT&T said Thursday that a nationwide cellphone outage that affected more than 1.7 million customers and disrupted 911 services in several states was caused by an error made while it was expanding its network — not by a cyberattack.
The outage prompted wide concern, particularly over the loss of emergency services — with some 911 centers urging customers to use a landline for any calls, or find a cellphone that uses a different carrier.
It also prompted a flood of speculation over the cause, though experts early on suggested a technical mishap was more likely than some of the other suggestions, including a cyberattack or a solar flare.
National Security Council spokesman John Kirby said the FBI and the Department of Homeland Security are looking into the outage. The Federal Communications Commission is also investigating the outage, a spokesperson said.
