GX 400 - Sprint Modem Problems

I am having trouble with a GX 400 modem that is currently on the SPRINT network. We use these modems to program road side message boards via a laptop or desktop. When I am on my laptop and connect through wifi via a Sprint Netgear hotspot everything works perfect. But when I am on any other computer on any other network(Verizon/Comcast/At&T) I cant connect to the modem. I have called SPRINT and they couldn’t help - Any suggestions?

It seems modem IP can be reached only within Sprint network. So account is restricted somehow … it all depends how Sprint has setup that account. Sprint Data Specialist (tier 2) should be able to change the account restrictions…