The outage affected both iPhone and Android phones, as well as disrupting Wi-Fi calling services to these devices which would typically be fallback solutions. As of 6:15 p.m. ET, Verizon reported that service has started to be restored, with working cotinuing to restore service for everyone.

The Federal Communications Commission said on Monday that it was investigating a Verizon network outage across the United States after thousands of users reported outages. Chicago and Indianapolis were among the hardest-hit cities and some iPhone users were stuck in "SOS" mode.

Some Verizon customers across the U.S. were hit by a service outage Monday. The issue appeared to knock out cellphone service for tens of thousands of Verizon users. Data from outage tracker DownDetector shows that reports topped 100,