It wasn’t a cyberattack but a technical error that caused AT&T’s massive outage on Thursday, Feb 22. In a statement, AT&T said the outage began in the morning hours as the company worked to expand its network.

“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,” the company’s statement read. “We are continuing our assessment of today’s outage to ensure we keep delivering the service that our customers deserve.”