How to fix "Can't open ms-xbl-multiplayer link"?

Hi CraneJackal, sorry to hear that.
Please tell me:

May I know if the problem happens with a different game or only Sea of thieves?

Also, did you tried playing and inviting your friend using the cloud gaming feature via Microsoft edge or Google chrome?

And if possible, try using a different PC to see if something similar happens

It appears that the game bar is looking for the app on your PC. It doesn't go to cloud gaming anymore. I hope it is a bug in the Game Bar/Xbox app/

I don't use the cloud for any other games other than sea of thieves, as far as I can tell it's only been with sea of thieves. I normally join them instead of inviting my friend.

Hi and thanks for reaching Microsoft Xbox gamer's community.
My name is Josef.
I'm an Independent Advisor

Hope you're doing great today despite this CRANEJACKAL

Usually that message appears when something’s going on with the game bar, but let’s try to isolate the problem a bit more:

0. Double check if everything in your system is up to date

Open Settings, click Update and Security and then Windows Update
Click Check for Updates

Click the Download and Install Now option, if available (Install optional updates as well)

Then, check the Microsoft Store for any updates on the Xbox apps and its services and update everything too. (Click on get updates)

If everything looks good proceed:

1.
Go to windows settings > apps > search for Xbox game bar app > click on it and select advanced options.

After that, click repair and then reset

Then do the same for the Xbox app:

Go to windows settings > apps > search for Xbox app > click on it and select advanced options.

After that, click repair > then reset and try again

2. Reinstall the game bar via powershell command

Right-click on the Start button and select Windows PowerShell (Admin) from the pop-up menu.

Copy and paste the following command in PowerShell and hit Enter to uninstall the Game Bar from your system.

Get-AppxPackage Microsoft.XboxGamingOverlay | Remove-AppxPackage

Now head over to Microsoft Store and search for Xbox Game Bar, install it and give it a new try

3. Delete the registry keys associated with the game bar :

Press Windows key+R then type regedit and press Enter.
Go to this path (expand the folders using the little ">")

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\GameDVR

Once there delete all the keys except (Default), restart your PC and try again

Hi Tanner, my name is Rodrigo. I'm an Independent Advisor and a member of the Microsoft community and I'd love to assist you today.

I am sorry to hear that.

Please, try the steps below:

Press Windows key +X, select Windows Powershell (Admin).

Type the command on the terminal window (Press Enter to confirm):

Get-AppxPackage *windowsstore* | Remove-AppxPackage

Type the next command:

Get-AppxPackage *xboxapp* | Remove-AppxPackage

Reboot your computer and type in the last command:

Get-AppxPackage -AllUsers| Foreach {Add-AppxPackage -DisableDevelopmentMode -Register “$($_. InstallLocation)\AppXManifest.xml”}

Let me know if it works!