AT&T reveals likely cause of outage that affected customers nationwide

AT&T said the network disruption that caused tens of thousands of customers to lose cellular service Thursday was not the result of a cyberattack.

After service was fully restored at around 6 p.m. ET, the mobile phone service provider revealed the results of its initial investigation into the outage.

"Based on our initial review, we believe the outage was caused by the application & execution of an incorrect process used as we were expanding our network, not a cyberattack," AT&T posted on X.