AT&T, Verizon and T-Mobile customers hit by widespread cellular outages in U.S.

AT&T’s widespread outage that left thousands without service for hours Thursday was likely caused by a process error — not a cyberattack, the carrier said.

The trouble started early Thursday, but by afternoon AT&T reported that service had been restored to all customers.

Based on an initial review, the company thinks the outage “was caused by the application and execution of an incorrect process used as we were expanding our network, not a cyber attack,” it said Thursday evening.

Over 32,000 AT&T outages were reported by customers about 4 a.m. ET Thursday. Reports dipped then spiked again to more than 50,000 around 7 a.m., with most issues reported in Houston, Chicago, Dallas, Los Angeles and Atlanta, according to the site.

That number surged to more than 71,000 just before 8 a.m. ET.

AT&T acknowledged the issue Thursday morning, saying: “Some of our customers are experiencing wireless service interruptions this morning.”

Other cellular providers, including Verizon, T-Mobile and Cricket Wireless, also reported outages. Verizon and T-Mobile said those affected had been trying to contact AT&T users.

Verizon said Thursday morning that the outages are not affecting its network directly, only customers trying to reach another carrier.

T-Mobile also said early Thursday that the network didn’t suffer an outage.

Cricket Wireless, which is owned by AT&T and uses its network, also experienced cellular problems. More than 13,500 customers reported outages as of 8 a.m. ET Thursday. The number dipped to around 10,000 by 10 a.m.

“Allow us to explain that there is a nationwide network incident impacting multiple services,” the company wrote on X. “It is Cricket’s top priority to restore service to full capacity as quickly and safely as possible.”

Service has since been restored for all affected AT&T customers.

“We have restored wireless service to all our affected customers. We sincerely apologize to them. Keeping our customers connected remains our top priority, and we are taking steps to ensure our customers do not experience this again in the future,” the company said in a statement.

AT&T has not provided additional details about what triggered the nationwide service disruption, and the U.S. Cybersecurity and Infrastructure Security Agency said there is no indication of a cyberattack.

The most likely cause of the outage “is a cloud misconfiguration” which is “a fancy word for saying human error,” Lee McKnight, an associate professor at Syracuse University’s School of Information Studies, said in a statement.

The Federal Communications Commission is actively investigating the incident. The Federal Bureau of Investigation and Department of Homeland Security are lending a hand.

The outages posed a concern to some customers Thursday morning about being able to reach 911.

The San Francisco Fire Department said on X that it was aware of an issue affecting AT&T wireless customers’ making and receiving phone calls, including to 911.

“The San Francisco 911 center is still operational,” the office said. “If you are an AT&T customer and cannot get through to 911, then please try calling from a landline. If that is not an option then please try to get ahold of a friend or family member who is a customer of a different carrier and ask them to call 911 on your behalf.”

Similarly, Chicago’s Office of Emergency Management and Communications, Virginia’s Prince William County Police Department, and North Carolina’s Charlotte-Mecklenburg Police Department issued warnings on X alerting the public about the outage while acknowledging some customers were briefly unable to contact 911.

Atlanta Mayor Andre Dickens said in an earlier statement that the city was gathering information to assist in resolving the issue.

“Atlanta’s e-911 is able to receive inbound and make outbound calls. We have received calls from AT&T customers that their cellular phones are in SOS mode,” Dickens said.

During the outage, iPhone users who saw SOS displayed in their status bar could still make emergency calls through other carrier networks.

Agencies across the country urged people to refrain from calling 911 to test their service. The line is for real emergencies only.

Marlene Lenthang

Breaking News Reporter

Katherine Itoh

Katherine Itoh is a news associate for NBC News.

Crystal Minaya

Josh Cradduck

Elizabeth Maline

Austin Mullen

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Rebecca Cohen