AT&T wireless customers nationwide reported not being able to make or receive calls Wednesday.
According to maps on Outage.Report and Down Detector, the most severely hit areas in California were in the Bay Area and around Los Angeles, with Sacramento and Elk Grove still experiencing some problems as of 6 p.m.
The company took to Twitter to say the fix is simple: Just restart your phone.
As of 6 p.m., the Outage.Report map was still showing a lot of red, including in eastern Texas, southern Louisiana, central Florida and in the New York City area. Several major U.S. cities were also affected.