Upnp on xbox is unsuccessful on mobile hotspot

What changed all of a sudden with the mobile hotspot? I have been using it for almost a year to play games online on my xbox with no issues, and now all of sudden it quit working 5 days ago. Not happy with how much I pay, to not get to use features I’m paying for. I specifically bought a nighthawk lte mobile hotspot and put that on my plan to use for online gaming. Tell me please how to fix this? I live in the country and this is my only option.