T-Mobile: Outage caused by "back-end system software error"

T-Mobile has issued a statement explaining its Tuesday night network outage that affected 5 percent of its customers in the U.S. The mobile carrier said that a "back-end system software error" caused abnormal congestion and that it is taking steps to ensure the issue doesn't happen again, Phone Scoop reports.

As we reported Wednesday, the outage began at about 5 p.m. EST and appeared to affect voice, SMS, and in some cases, data connectivity, depending on the device and location. The company says that service was fully restored by 1:25 a.m. early Wednesday morning.