AT&T outage: Cause was due to ‘incorrect process’ used to expand network, company says

AT&T said the outage on Thursday that left tens of thousands of customers without service for hours was due to "an incorrect process" which was used as the company was expanding its network, according to the company’s website. 

"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 cyber attack," according to an update from AT&T. 

The company said its assessment of Thursday’s outage is ongoing at this time. 

FILE - A visitor walks past US multinational telecommunications AT&T logo. ( PAU BARRENA/AFP via Getty Images)

In addition to AT&T’s incident, other wireless carriers such as Cricket Wireless, T-Mobile, Verizon and Boost Mobile reported outages. 

Cricket Wireless had the most reported outages after AT&T, followed by Verizon and T-Mobile and Boost Mobile, respectively. 

Despite DownDetector.com reflecting more than 1,800 outages from T-Mobile customers earlier on Thursday, the company said their systems were operating normally. 

"Down Detector is likely reflecting challenges our customers were having attempting to connect to users on other networks," T-Mobile said. 

Verizon also noted its networks were working properly but said some customers were having issues calling or texting other customers who were served by different carriers. 

"We are continuing to monitor the situation," Verizon said. 

RELATED: AT&T outage: How to communicate when networks go down

AT&T phone outage

DownDetector.com, an outage tracking site, showed thousands of outages reported starting around 3:30 a.m. ET. Six hours later, AT&T had more than 73,000 outages by about 9:30 a.m. ET. 

Outages were reported in many major U.S. cities, including New York, Los Angeles, Atlanta, Houston, Dallas, Chicago, and Philadelphia. 

"Some of our customers are experiencing wireless service interruptions this morning. We are working urgently to restore service to them. We encourage the use of Wi-Fi calling until service is restored," AT&T said in a statement. 

AT&T has more than 240 million subscribers in total. 

RELATED: AT&T outage: What works, and what doesn’t, without cell service on your phone 

At 11:15 a.m. ET, AT&T said 75% of the customers had service. Then, at 3:10 p.m., the carrier confirmed all service was restored.

— February 22, 2024, 3:10 p.m. ET

Kelly Hayes contributed to this report. This story was reported from Los Angeles.