Wireless customers of Verizon and AT&T have found that they cannot make calls, send or receive text messages, or download any mobile data. As of this article's publication, it appears the problem has yet to be resolved.

Users took to social media throughout the morning to complain that their phones were showing "SOS" mode, which allows emergency calls but nothing else. This is what phones sometimes offer when the user has no SIM registered on the device. Resetting the device and other common solutions do not resolve the issue. For much of the morning, Verizon offered no response to the reports.

Within hours, more than 100,000 users reported problems on the website Downdetector. The problem does not appear isolated to any particular part of the country; users in California reported problems, and so did users on the East Coast and in Chicago, among other places.

By 10 am, some AT&T users also began reporting problems. Outage maps based on user-reported data found that the outages were especially common in parts of the country otherwise affected by Hurricane Helene.

After a period of silence, Verizon acknowledged the problem in a public statement. "We are aware of an issue impacting service for some customers," a spokesperson told NBC News and others. "Our engineers are engaged and we are working quickly to identify and solve the issue."

However, the spokesperson did not specify why the outage was occurring. It's not the first major online service outage this year, though. AT&T experienced an outage previously, and the CrowdStrike-related outage of Microsoft services caused chaos and made headlines in July.