RUTM54 disconnects right after connecting with Verizon SIM

I currently have three RUTM54 modems in the USA equipped with Verizon SIM cards. They connect successfully at first, but the connection drops immediately afterwards, and the log says that the modem was disconnected by the user. Does anyone have a tip on where I should look for the cause of this issue or which settings I should check?

Hello!

Thank you for your inquiry!

In this case, we would suggest the following:

Checking your APN settings - if you do not know what it is meant to be, please inquire to your internet service provider;
Contacting your service provider to check if the IMEI of the device has not been blocked;

This information will allow us to investigate further.

Kind regards,
Laura.