AT&T error led to outage, officials say
The national cellphone system failure that affected more than 1.7 million customers and disrupted 911 services in several states was because of an error made while AT&T was expanding its network, the company said.
Spokesperson Jim Greer said AT&T would continue to assess the glitch, which began early Thursday and quickly grew to tens of thousands of reports on the phone system tracking website Downdetector. He said service was restored to all customers by about 2 p.m. Thursday.
“Based on our initial review, we believe that today’s outage was caused by the application and execution of an incorrect process used as we were expanding our network, not a cyberattack,” Greer said in an email.
Still, the incident prompted at least three federal agencies, including the FBI, to investigate, authorities said.
It’s unclear how many of AT&T’s roughly 71 million postpaid wireless customers were affected. The network intelligence firm Ookla, which runs Downdetector, counted about 1.7 million unique customers, but that number is far from complete because it relies only on self-reported instances when customers could not get a cellphone signal.
Representatives of several other carriers, including Verizon and T-Mobile, said their networks were not affected and that reports from their customers about service interruptions may have come from people who tried to call AT&T customers. Cricket Wireless, a budget carrier owned by AT&T, had more than 12,000 lack-of-service reports from customers at one point Thursday.
The failure prompted wide concern, particularly over the loss of emergency services — with some 911 centers in California, North Carolina, Texas and elsewhere urging customers to use a landline for any calls or find a cellphone that uses a different carrier. It underscored the influence that a handful of large cellphone carriers hold over Americans’ everyday communications and access to lifesaving services.
On Thursday, state police in Massachusetts said 911 centers were being flooded with “test”
calls, while officials in one Ohio town said the failure also affected fire alarms. One West Virginia county encouraged residents to text 911 as a last resort.
It also prompted a flood of speculation over the cause, though experts early on were leaning toward a technical mishap as opposed to a cyberattack, solar flare or other cause.
“It most likely seems like a software update gone wrong,” Northeastern University professor Josep Jornet said Thursday.
National Security Council spokesman John Kirby said the FBI and the Department of Homeland Security are investigating, along with the Federal Communications Commission, a spokesperson said.