Why does my phone say SOS? AT&T cellphone outage affects Arizona. Here's what to know

Hundreds of Arizona cellphone users were affected by a telecommunication outage on Thursday morning.

AT&T customers were among those most impacted, followed by Cricket Wireless users, according to Downdetector.com, a website that monitors real-time outages.

The website showed significant impacts in Arizona, with nearly one-fourth of reports coming from the Phoenix area. Other cities largely impacted by the outage included Houston, Texas; Charlotte, North Carolina; Chicago; and New York City.

The surge in outage reports began around 5 a.m. and was still increasing as of 7:45 a.m. Arizona time on Thursday. Estimates showed that more than 300 AT&T customers and dozens more from Cricket Wireless were affected.

AT&T spokesperson Rebekah Drennon said outages in the Phoenix area were due to third-party fiber damage and experts were working to restore cell service to customers.

"We’re in contact with the local provider, who is working to resolve issues outside of our network, so that we can fully restore service to customers as quickly as possible," Drennon said.

If you get your cellphone service from these providers and own an iPhone device, on Thursday morning you likely saw an SOS icon at the top of your screen, where the cellphone service usually displays. Here's what it means and how to fix it.

Why does my phone say SOS?

An SOS symbol appeared on the screens of iPhone users with AT&T and Cricket Wireless, where cell service bars are normally shown.

According to Apple support, if you're having trouble with phone service and you see SOS or "SOS only" in the status bar, it means your device can still make emergency calls despite not being connected to a phone network.

"When you make a call with SOS, your iPhone automatically calls the local emergency number and shares your location information with emergency services," according to Apple. "In some countries and regions, you might need to choose the service that you need.

If your cellular issue has been solved and you still can't connect to a cellular network, contact Apple support.

Is it too hot for your phone? How to stop yours from overheating in Arizona's high temps

This article originally appeared on Arizona Republic: Why does my phone say SOS? What to know about AT&T outage