Xbox One will not connect to Xbox Live using new CenturyLink C4000LG Modem - "UPnP not...

Have you tried connecting with a cable? I know it may not be ideal but this would confirm whether it is an issue with the Wi-Fi or if it's an underlying issue with that modem and Xboxes

I have seen a comment that the 4000 modems had issues with older Wi-Fi drivers (which would likely be the case due to the age of the XB1 platform)...trouble is I suspect that's not something that can be fixed on an Xbox (a PC would likely have an option)

Not sure if this is any help but this has a troubleshooting for uPNP and also has a XBL specific section on it:

https://mysupport.zyxel.com/hc/en-u...PE-CenturyLink-NAT-UPnP-Troubleshooting-Guide

I have port forwarding but I don't know how to use it

I'm also having the same issue with my Xbox one got the C4000BG CenturyLink router. Tried everything as well (

Thank you for your quick response Mohammed. The DMZ option did not work, and I do not appear to have access to "Port Triggering" features on my modem (we do not have a router, just the one modem). Do you or others have any other suggestions?

If UPnP still isn’t working after trying the steps you mentioned, or isn’t supported on your gateway/router, you can also try using the router’s DMZ, or Port Triggering features.

Find more about this here: “UPnP Not Successful” appears in your network settings | Xbox Support