I've found a workaround for this issue for Xbox One, One S & X, Series X|S. If you are having this problem, try the following steps. If it is your friend with this problem, have them follow these steps.
The steps I did to fix this: Open your Xbox Home menu. Go to Profile & System. Go to Settings, General, Network settings. Click Advanced settings, Alternate port selection. Click Manual. Look at the number of your current selected port, click it and select a port with a higher displayed value then your current port. Click continue. Make sure the NAT type option shows Open. If not, select another port. Restart your console once you see NAT type: Open. Login to your Xbox account and load up Minecraft. Try joining a friend. (or load up a world and try having a friend join you if they are the one having the problem) If done correctly, you, or your friend, should be able to join the world.
I've found a workaround for this issue for Xbox One, One S & X, Series X|S.
If you are having this problem, try the following steps. If it is your friend with this problem, have them follow these steps.
The steps I did to fix this:
Open your Xbox Home menu.
Go to Profile & System.
Go to Settings, General, Network settings.
Click Advanced settings, Alternate port selection.
Click Manual.
Look at the number of your current selected port, click it and select a port with a higher displayed value then your current port.
Click continue.
Make sure the NAT type option shows Open. If not, select another port.
Restart your console once you see NAT type: Open.
Login to your Xbox account and load up Minecraft.
Try joining a friend. (or load up a world and try having a friend join you if they are the one having the problem)
If done correctly, you, or your friend, should be able to join the world.