Thousands of Verizon users across the U.S. reported service outages Monday morning, with many phones getting stuck in SOS mode, signaling an inability to connect to cellular service.

The outages were primarily concentrated on the East Coast and the Midwest, with over 100,000 incidents reported by 11 a.m. according to Downdetector.

SOS mode, a feature introduced with the iPhone 14, allows users to make emergency calls when regular cellular service is unavailable and automatically turns off when the service is restored.

Verizon acknowledged the issue and said its engineers are working swiftly to resolve it, while frustrated users voiced their concerns on social media.