I asked Verizon spokesperson David Weissmann to comment: here's his texted reply -
We are currently experiencing a network issue impacting wireless service for some customers in the Upper Midwest including the Rockford, IL, and Davenport, IA metro areas. Our engineers and technicians have identified the hardware issue and are working to resolve it as quickly as possible. Affected customers can still make and receive calls by enabling WiFi calling on their devices. Instructions on how to enable this free service can be found at ...
I asked Mr. Weissmann if this is an FCC-reportable outage, and how many customers are affected, and I'm waiting for his reply.