The cause was apparently a fiber line cut in New York that was owned by Lumen. The cut seemingly caused reduced availability to T-Mobile’s authentication and provisioning services, creating a backlog and overloading them.
The result was that when devices attempted to authenticate on the T-Mobile network, they were met with silence. Some devices that were already on a stable connection, especially home internet devices, remained connected with no issues.
One source claims there was also a separate fiber cut in Kentucky, however it’s unclear if this also impacted the network.
Neville Ray, President of Technology at T-Mobile, confirmed the fiber outage on Twitter.
Engineers worked quickly to resolve the issue, and as of 1am Eastern services were mostly restored.
The outage is yet another blow to the “Uncarrier”, after the company suffered a data breach last month. It also isn’t a good look for the carrier after they spent what is likely millions of dollars advertising during the Super Bowl.
During the initial moments of the outage, reports were coming in that Verizon and AT&T were also affected. However, this appears to be not the case. Typically when a major carrier like T-Mobile goes down on such a scale, there is a bit of a residual wave of reports on other networks. Even home internet providers were shown to be having outages, even though they were not.
Customer service was so overwhelmed with calls that the care line was turned off for a few hours. Calls to the T-Mobile support line were met with messages saying they were closed or unavailable.
T-Mobile customers who still do not have service should try toggling airplane mode or rebooting their device.