Americans Wake To Widespread AT&T Cellular Outages

Final update Residents of the United States woke this morning to widespread outages of AT&T's cellular service.

Problems with the telco giant began flooding into crowd-sourced outage monitor Down Detector at roughly 0400 Eastern (0100 Pacific) and haven't slowed since, with more than 73,000 AT&T outage reports submitted at the time of writing.

T-Mobile US and Verizon subscribers also reported problems, but those appear to be knock-on effects of the main AT&T breakdown, such as T-Mo users finding themselves unable to get through to AT&T numbers and blaming their own carrier.

"T-Mobile did not experience an outage. Our network is operating normally," a T-Mo US spokesperson told The Register. "Down Detector is likely reflecting challenges our customers were having attempting to connect to users on other networks." 

Verizon had much the same to say, telling us that its network is operating normally, and any issues likely relate to Verizon customers trying to reach those on other carriers. With most of the reports pertaining to AT&T, and T-Mo and Verizon's denials of anything wrong on their end, the outage appears to be primarily an AT&T issue, which the carrier has confirmed.

"Some of our customers are experiencing wireless service interruptions this morning.  We are working urgently to restore service to them," an AT&T spokesperson told us. "We encourage the use of Wi-Fi calling until service is restored."

No explanation for the outage, which is ongoing as of publication, was given. 

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The outage is severe enough that affected AT&T customers appear to be unable to place or receive any phone calls, including to 911, the San Francisco Fire Department warned folks on Twitter.

"If you are an AT&T customer and cannot get through to 911, then please try calling from a landline," the SFFD said - but "do not call or text 911 simply to test your phone service," the Fire Department added. 

A map of AT&T outages as of 0838 Eastern Time, Feb 22 - Click to enlarge

A map of AT&T outage reports shows several major metropolitan areas are affected at the time of publication, including Atlanta, Dallas and Houston. 

Cellular towers have classically been owned by the carriers, but that's changed in the US in recent years - most towers are now owned by tower real estate investment trusts like American Tower and Crown Castle, who've bought up tens of thousands of cell towers. Many of those towers were purchased from AT&T, Verizon and T-Mo, making even the largest US cellular providers look more like the small virtual network operators their hardware has classically supported. 

With that in mind, we reached out to some of the major cell tower firms to see if they had anything to report. We'll update this story if we hear back, and as the situation evolves. ®

Updated to add at 1650 UTC

A spokesperson for AT&T has let us know the carrier thinks its network is recovering: "Some of our customers are experiencing wireless service interruptions this morning. Our network teams took immediate action and so far three-quarters of our network has been restored. We are working as quickly as possible to restore service to remaining customers."

Cloudflare has a graph showing a significant drop off of IPv4 and IPv6 connectivity for AT&T, leading some network administrators to speculate it's a BGP issue.

Final update at 0120 UTC, February 23

AT&T says it has fully restored its subscribers' wireless connectivity. It also denied suggestions this was all the result of a cyberattack, and instead blamed "the application and execution of an incorrect process as we were expanding our network." A bad software or system update, in other words.

"We are continuing our assessment of today’s outage to ensure we keep delivering the service that our customers deserve," the telecoms giant said in a statement to media.