Why Is At&Amp;T Down. Cellphone network thursday appeared to be the result of a technical error, not a malicious attack. The widespread at&t cellular outage was caused by a software update, the network said.
While at&t provided no official reason for the outage, the issue appears to be related to how cellular services hand off calls from one network to the next, an. At&t says cell service is back after a widespread outage and some disrupted 911 calls.