They're seeing the "blue screen of death"
Some T-Mobile iPhone users on Wednesday are reporting a “blue screen of death” followed by their devices restarting.
Users flustered by the problem say their iPhones are displaying the ominous blue screen randomly for a split second, then rebooting, often at 10 to 30 minute intervals, MacRumors reports. iPhones that have experienced the issue so far include the iPhone 6 Plus, 6 and 5s across several versions of iOS 8.
Though T-Mobile has not addressed the issue publicly, some users speculate the issue may be a memory problem. The carrier’s support staff has recommended to customers who call-in to try a hard reset. And if that doesn’t work, customers should try clearing out old text messages, then restoring their iPhones to factory settings with iTunes.
T-Mobile has not yet responded to TIME’s request for comment.