Verizon said its network is fully restored, returning mobile phone service to customers across the country after an outage on Monday that left many people unable to make or receive calls for much of the day. 

People across the country said their phones had no service except for SOS mode, which means their phones are having trouble connecting to a wireless network. However, when a phone is in SOS mode, it can still make emergency calls, such as 911, by connecting to other carriers, according to Apple.

The outage began shortly after 9 a.m. E.T. on Monday and lasted into the evening. At 8 p.m. Verizon told CBS MoneyWatch that its engineers had fully restored the network after a “disruption that impacted some customers.”

“Service has returned to normal levels,” the spokesperson said. 

What if your phone is still in SOS mode? 

Verizon said that people who are still having trouble connecting to its network should restart their mobile device. 

People with iPhones can also try reconnecting to their cellular network by going to settings, turning on “airplane mode” for at least 15 seconds and then turning off airplane mode, according to Apple. 

“We know how much people rely on Verizon and apologize for any inconvenience. We appreciate your patience,” Verizon said.