A large-scale blackout occurred for mobile phone users in the United States on the 22nd, causing temporary interruptions to calls, text messages, and emergency services in major cities including San Francisco. Federal authorities also launched an investigation due to concerns that it was caused by a cyber hacker attack.
The incident resulted in cell phone outages for AT&T, Cricket Wireless and other companies. AT&T, whose 5G network covers a population of 240 million in the United States, had the most serious problem.
The U.S. Federal Communications Commission and relevant agencies are investigating the incident, but AT&T stated earlier that mobile phone services across the United States had returned to normal after being interrupted for several hours. However, the company did not provide more detailed information about the cause of the outage.
AT&T shares also fell 2.4% in afternoon trading on the incident. As of approximately 2:47 PM ET (1947 GMT), DownDetector.com reported about 3,255 outages.
Doug Madory, a director at Internet analytics firm Kentik, stated that it was unclear what exactly happened at AT&T from an external perspective, but he suspected it was the result of malicious activity. However, AT&T stated in a release: ‘If we detect any malicious activity, we will respond accordingly.