Hi, I am Van. I'll be glad to assist you today.
This normally happens if the Multiplayer option is disabled in your Xbox privacy settings. Please follow the steps below to enable this option.
- Login to Xbox.com with your Microsoft account.
- Click your account at the upper-right corner of the page, then select Xbox profile.
- On your profile page, click settings, then select Safety & Privacy > Manage safety & privacy settings.
- In the Privacy & online safety page click the "Xbox and Windows 10 Online Safety" tab
- Scroll down and look for the "You can join multiplayer games" option, then click Allow to enable it. Click submit at the bottom of the page to save the setting
- Relaunch the game and check if you can now play in multiplayer.
Note: You will not be able to see the Privacy & Online Safety section if you are a family group member. You will need to ask the family group organizer to edit your settings
Please let me know if you need any further assistance. I will be glad to assist.