If you have a closed or moderate NAT type on your Xbox One / X|S consoles, these solutions below can help you get an open NAT.
Testing NAT type on Xbox:
To test and see your current NAT type, go to Settings → Network settings →Test NAT type.
Restarting your router
You're probably thinking that this is a really obvious thing to do but believe me, a lot of people forget. Make sure to reset your router and wait 30 seconds to a minute before turning the router back on. Once you've done this, go back into your consoles settings and test your NAT type again.
Hard reset / Power cycle console
To hard reset an Xbox One/ X|S console, hold down the power button for 10 seconds. Then, turn the console back on and go to network settings to check your NAT type. To power cycle your Xbox One/ X|S console, hold down the power button for 10 seconds. Once the console is completely switched off, unplug the power cord from the back of the console and keep it unplugged for 5 minutes. Once 5 minutes have passed, plug the power cord back into the console and turn it on. Then, go to network settings and check your NAT type.
Turn off [Instant On] mode and turn on [Energy Saver]
By disabling ‘Instant On’ and enabling ‘Energy Saver’ your console will reboot every time you power on. This will help the console renew its UPnP leases for Open NAT. Unfortunately this also means dealing with much longer start up times.
To do this method, test your multiplayer connection and wait for it to complete finish. Once the test has completed, press LT+RT+LB+RB all together to access the advanced screen. Your console will now try to release it's UPnP leases for an Open NAT. This method may take several minutes to complete.
Different NAT types and what other NAT types the can connect to:
|Type of NAT||Open||Moderate||Strict/Closed|
Open NAT is the most optimal type available for a player. Of you have an Open NAT type, you shouldn't have any issues connecting to multiplayer games and joining Xbox Live parties. With an open NAT type, you can also host multiplayer games on peer-to-peer connections.
With a Moderate NAT type, you may experience some issues when connecting to multiplayer games or Xbox Live parties. Although you are able to connect to multiplayer games, you may experience more lag and you won't be selected as a host in peer-to-peer connections.
This is the worst NAT type a player could have. Having a strict NAT means you won’t be able to connect to multiplayer games or Xbox Live parties without issues. Lag in multiplayer games will increase to where it's unplayable and you will disconnect frequently.