AT&T Inc. said Thursday its cellular network has been restored, after widespread “wireless service interruptions” affected some of its customers earlier in the day, following user reports of outages.
Tens of thousands of AT&T T, -2.41% users had flagged service disruptions on Downdetector shortly after 11 a.m. Eastern time. AT&T said it took “immediate action” to address the issues.
“We have restored wireless service to all our affected customers,” AT&T said on its website Thursday afternoon. “We sincerely apologize to them … we are taking steps to ensure our customers do not experience this again in the future.”
AT&T blamed the outage on a software error, rather than anything malicious. “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 said in a statement.
Earlier, National Security Council spokesman John Kirby said the Federal Communications Commission, the Department of Homeland Security and FBI were looking into the outage and the possibility of a cyberattack.
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Shares of AT&T fell more than 2% on Thursday.
While customers of Verizon Communications Inc. VZ, -0.90% and T-Mobile US Inc. TMUS, -0.30% also flagged service issues on Downdetector, those carriers suggested that reports from their customers were due to problems contacting customers on AT&T’s network.
“Verizon’s network is operating normally,” a spokesperson said. “Some customers experienced issues this morning when calling or texting with customers served by another carrier.”
T-Mobile “did not experience an outage,” a spokesperson there said. “Our network is operating normally.”
Shares of Verizon were down about 1% in Thursday action, while T-Mobile’s stock was off fractionally.
Mike Murphy contributed to this report.