How to keep NAT type on open and fix "UPnP not successful" error?

I don't know how useful this information will be but it's better to put it out there than not. I've had the exact same scenario happen to me up until recently, nothing I did fixed it and I had pretty much given up on playing anything online with my xbox. A few days ago my service was shut off because I forgot to pay the bill and didn't get it paid until the next day. Once I had internet again my xbox could play online just fine, and a few days later it still works fine. This makes me believe the problem is mostly if not completely on T-Mobile's side since literally nothing else changed in the day my service was shut off. Hopefully this post helps in figuring out how to fix this issue. (Edit) I should also probably clarify that I don't ever get an Open NAT Type, but I can still play games online with minimal lag. In the months where the issue was occurring I couldn't play anything online except Overwatch 2 and I could preform limited online actions on Warframe (Usually trading quickly before getting disconnected). Since the issue has cleared up my NAT Type is usually Moderate but still with the UPnP error appearing. I'm not going to mess with my settings just incase it breaks anything that was fixed.

Thank you for contact us! I'm Anderson, an Independent Consultant and a Microsoft user like you.

good evening

I'm sorry to hear that you are experiencing issues with your NAT type and UPnP error message. Here are a few things you can try to troubleshoot the issue:

Make sure that UPnP is enabled on your gateway. UPnP stands for Universal Plug and Play, and it is a protocol that allows devices on your network to automatically discover and communicate with each other. To check if UPnP is enabled, log in to your gateway's web-based interface and look for an option to enable UPnP.

Reset the network settings on your console. This can help resolve any network-related issues that may be causing the NAT type and UPnP error message. To reset the network settings on your Xbox Series X, go to "Settings," then "General," and then "Network Settings." From there, select "Reset Network Settings."

Try using a wired connection instead of a wireless connection. A wired connection can be more stable and may help resolve the NAT type and UPnP error message. To use a wired connection, connect your console to the gateway using an Ethernet cable.

Check for any firmware updates for your gateway. Outdated firmware can cause connectivity issues, so it's a good idea to keep your gateway's firmware up to date. To check for firmware updates, log in to the web-based interface of your gateway and look for an option to check for updates.

I hope these suggestions help!

I can't customize or change anything regarding my gateway due to the way it's set up, including turning UPnP on or off, I can't do manual updates to it either. I've also cleared my alternate MAC address as you suggested (multiple times), that didn't work either. I'm also using an ethernet cable, I have been for years. This issue is becoming very frustrating.

Hello orishaked,

Thanks for posting on the Xbox forums. We understand that you are interested in getting an open NAT type, and you are receiving an error message stating that UPnP was not successful. Which troubleshooting steps have you attempted thus far? We
have a support article that provides solutions for
the UPnP error message. We need to fix this error message first before we can resolve the NAT issue. Be sure to let us know the results
orishaked!

In this case, please check your current NAT type:

Press the Xbox button > Select Profile & system > Settings > General > Network settings. Under Current Network Status, the NAT Type field displays your current NAT type.

You need your NAT type to be Open. You also want to be sure there are no errors such as Double NAT detected or UPnP not successful displayed.