Mobile carrier Verizon experienced a massive outage on Monday. US users were unable to make calls or send messages for several hours. Downdetector received more than 1.5 million crash reports between 8:00 AM and 4:00 PM EST. In the evening, the company was able to resume work.

Many customers’ phones were in SOS mode, according to a Verizon support message. According to the report, “the outage affected data, voice and text services.” At one point, Downdetector had three fifteen-minute periods with more than 100,000 user reports of problems.

According to The Verge, communications outages were reported from Padwick, Birmingham, Fairhope, Montgomery, Brookland and 1,678 other cities during the incident. Verizon engineers fully restored the outage at 7:18 PM ET.

The US Federal Communications Commission also released a statement saying it was aware of the outage and that the agency was “working to determine the cause of these service outages.”