Thousands of AT&T subscribers across the US experienced an hours-long network outage Tuesday that prevented them from placing or receiving calls, sending texts, or accessing the internet on their iPhones.

iPhone users began flooding AT&T's Help channel on X (formerly Twitter) and Downdetector around 2 p.m. PT with complaints of being locked in Emergency SOS via Satellite mode. Whenever iPhone users don't have cellular service or Wi-Fi, they'll see an SOS in the corner of their iPhone, indicating that they can use Emergency SOS via Satellite to get emergency help.

Read more: If Your iPhone Is Stuck in SOS Mode, Here's What You Should Do

AT&T blamed the outage on a software issue and said it is working on a solution.

"We are working to address a software issue that may affect the ability of a limited number of our customers to connect to our wireless network," AT&T said in a statement. "Keeping our customers connected is our highest priority, so we appreciate their patience as we work to resolve this issue."

An updated status statement issued by AT&T at 7:55 p.m. PT indicated that the issue had been resolved.

The SOS mode is a feature that Apple unveiled in 2022 that allows users to get in contact with emergency services and share their location with them, even if they don't have cellular network service. Emergency SOS via Satellite, which is available on iPhone 14 and newer phones, has been critical for helping people stranded reach emergency services without a phone signal. Last year, it helped a couple trapped in their car during the wildfires in Maui.

Apple didn't immediately respond to a request for comment.