Verizon mobile customers reported widespread outages across the US on Monday. Starting at around 9:30AM ET, hundreds of thousands of people flagged issues with their mobile service on Downdetector, which tracks user-submitted outage reports. The volume of reports spiked at almost 105,000 at 11:20AM, but were still reaching almost 59,000 at 12:52PM.

Many folks claimed they were unable to make or receive calls or exchange text messages. Those with an iPhone may be seeing “SOS” instead of the usual connection bars on the top right of their screen. That’s a common sight when there’s limited service or none at all. However, affected iPhone users can still make emergency calls via other networks.

A Downdetector heatmap suggested that the issue was most prevalent in New York, New Jersey, Georgia and elsewhere on the east coast and midwest. A narrow yellow band of reports was also emerging on the west coast as of 1:10PM ET. along with an intensifying heat spot in Los Angeles.

Verizon confirmed that service was affected for some customers. “Our engineers are engaged and we are working quickly to solve the issue,” the company wrote on X at 11:48AM. The cause of the outage is not yet clear.