Feds to probe T-Mobile over national mobile phone network outage

The chairman of the Federal Communications Commission says his agency will launch an investigation into a massive outage that left millions of T-Mobile phone customers unable to place phone calls or send and receive text messages earlier this week.

In a post on Twitter, FCC Chairman Ajit Pai called the hours-long outage “unacceptable.”

“We’re demanding answers,” Pai wrote on behalf of the FCC, “and so are American consumers.”

Customers of the third-largest mobile phone network began reporting problems on social media and the website Down Detector around 10 a.m. Pacific Time (1 p.m. Eastern Time). Those problems were largely centered on phone and text message service; data connections, including mobile Internet service, was unaffected.

In a blog post, a T-Mobile executive said the issue was centered on a glitch involving a third-party provider in the southeastern portion of the United States.

“This is something that happens on every mobile network, so we’ve worked with our vendors to build redundancies and resiliency to make sure that these types of circuit failures don’t affect customers,” Neville Ray, the company’s president of technology, wrote.

But for some reason, those redundant measures also failed on Monday, leaving millions across the United States without crucial access to their mobile phone services. The outage also affected T-Mobile’s prepaid mobile virtual network operator (MVNO) MetroPCS as well as third-party MVNOs like Straight Talk Wireless, Simple Mobile and Mint Wireless that use the T-Mobile network.

Customers of Verizon and AT&T, the two larger mobile phone networks, also reported problems with phone services, though officials at both companies said their networks were fine and customers were likely encountering problems contacting people who had service through T-Mobile.

The Desk was the first to report on the issue Monday afternoon. Within hours of the report, social media users and some security experts began suggesting a massive cyber attack known as a distributed denial of service, or DDoS, was likely to blame for the outage. During a DDoS attack, hundreds or thousands of computers flood a network with traffic, rendering a website or other service inaccessible.

But T-Mobile executives were quick to debunk these rumors, saying an “IP traffic related issue” was to blame for the outage, which lasted for at least seven hours before T-Mobile’s engineers were able to bring everything back to normal.

Matthew Prince, an executive with the security firm CloudFlare, speculated the problem occurred as T-Mobile was making network configuration changes. Though T-Mobile has yet to confirm this was the root cause of the problem, an earlier report suggesting the company would move around 1 million Sprint customers onto their enhanced 5G network listed Monday as the day for the changeover — and the network issues occurred that same day. (T-Mobile acquired Sprint earlier this year.)

Prince said the “cascading failures” was “almost certainly entirely of their [T-Mobile’s] own making.”

There’s no evidence T-Mobile did anything negligent or otherwise wrong in causing Monday’s issue, but that didn’t stop the head of the FCC from announcing an investigation against them.

But his bark will almost certainly be worse than his bite: Under Pai’s leadership, the FCC has largely taken a hands-off approach to mobile phone networks and other telecommunications companies, often scolding them when they are found to have committed some kind of wrongdoing, but rarely levying fines or other punitive measures against them.