To fix any issues you may be experiencing with Grounded multiplayer server visibility, you will need to locate the Xbox live settings on your computer.
You can do this by typing Xbox or Xbox Networking in the search box on the bottom left of your screen. Doing so will bring up the setting tab almost immediately. When the Xbox Networking tab opens up, you should see something like the image shown below.
Basically, you will want to have this program to run a check to see if there are any connection issues with the Xbox servers, as it can prevent players from joining your game on Steam.
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It should do this already when you open the Xbox Networking tab, but just in case, hit check again if needed and wait for it to perform the system check. If it comes back saying that the connection is blocked, click the button that says fix it, as shown below.
This will, in turn will have Xbox Networking try to fix the error that is blocking the Xbox Live multiplayer servers. When the program finishes the fix, you may need to restart your pc to fix the blocked connection.
This is because even after running the fix, it will still say blocked, so to change the connection from blocked, you will need to restart your computer.
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