I just received my Sim card from United Mobile.

I am in far north Michigan [NPI wireless GSM coverage]. The Sim card / phone is not working.

How can I test if this is a Sim card issue or does United Mobile not have an agreement with NPI Wireless.

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update

Ok, I got it to semi-work in Chicago. But the phone would state it was not authorized for outbound phone calls and a second later I would receive an inbound call that would connect me to the number that I attempted to dial.

Is that the way it is supposed to work?