An extensive service disruption experienced by numerous users under the AT&T network on Thursday is believed to have stemmed from a procedural error rather than a cyber intrusion, as disclosed by the telecommunications giant.
The disruption commenced early Thursday, yet AT&T announced in the afternoon that service had been fully reinstated for all subscribers.
Initial assessments suggest that the outage “resulted from the improper application and execution of a flawed procedure during the network expansion phase, as opposed to a cyber offensive,” the company stated on Thursday evening.
Approximately 32,000 AT&T subscribers reported service disruptions around 4 a.m. ET on Thursday. The number of reported outages fluctuated, peaking at over 50,000 by 7 a.m., with the majority concentrated in Houston, Chicago, Dallas, Los Angeles, and Atlanta.
Shortly before 8 a.m. ET, the reported outages surged to over 71,000.
AT&T acknowledged the issue on Thursday morning, citing “wireless service interruptions” experienced by some customers.
Additionally, other wireless carriers, including Verizon, T-Mobile, and Cricket Wireless, reported similar disruptions. Verizon and T-Mobile clarified that affected users were attempting to connect with AT&T subscribers.
Verizon specified on Thursday morning that the outages did not directly affect its network but impacted customers seeking to communicate with another carrier.
T-Mobile also confirmed on Thursday morning that its network had not experienced any disruptions.
Cricket Wireless, a subsidiary of AT&T utilizing its infrastructure, encountered cellular service issues as well. By 8 a.m. ET on Thursday, over 13,500 customers reported outages, though this number decreased to approximately 10,000 by 10 a.m.
In a communication on X, Cricket Wireless addressed the nationwide network incident affecting multiple services, prioritizing the swift and safe restoration of full service capacity.
Service has since been reinstated for all affected AT&T subscribers.
“We have successfully restored wireless service to all affected customers. We extend our sincere apologies to them. Ensuring uninterrupted connectivity for our customers remains our paramount objective, and we are implementing measures to prevent similar occurrences in the future,” the company stated.
AT&T has not furnished further details regarding the cause of the nationwide service disruption, and the U.S. Cybersecurity and Infrastructure Security Agency has not detected any indications of a cyber intrusion.
The leading cause of the outage is believed to be a “cloud misconfiguration,” a term synonymous with human error, according to Lee McKnight, an associate professor at Syracuse University’s School of Information Studies.
The Federal Communications Commission is actively probing the incident, with support from the Federal Bureau of Investigation and the Department of Homeland Security.
The outages raised concerns among some customers regarding their ability to reach emergency services, particularly 911.
The San Francisco Fire Department acknowledged an issue affecting AT&T wireless customers’ ability to place and receive calls, including emergency calls to 911.
“The San Francisco 911 center remains operational. If you are an AT&T customer experiencing difficulties contacting 911, please attempt to place the call from a landline. Alternatively, seek assistance from a friend or family member subscribed to a different carrier to contact 911 on your behalf,” the department stated.
Similarly, various agencies, including the Office of Emergency Management and Communications in Chicago, the Prince William County Police Department in Virginia, and the Charlotte-Mecklenburg Police Department in North Carolina, issued alerts on X, informing the public about the outage and acknowledging brief disruptions in 911 services.
Atlanta Mayor Andre Dickens indicated in an earlier statement that the city was gathering information to aid in resolving the issue.
“Atlanta’s e-911 system remains functional. We have received reports from AT&T customers regarding their cellular devices entering SOS mode,” Dickens stated.
During the outage, iPhone users encountering “SOS” displayed in their status bar could still place emergency calls through alternate carrier networks.
Authorities across the nation urged individuals to refrain from testing their 911 service, emphasizing that the line should be reserved for genuine emergencies only.