Start off by closing the game. Then follow the troubleshooting steps below for the store the game was purchased from.
🛠 Launch the Microsoft Store and check the account signed in is the game account that purchased the game and DLC.
If they are different, sign into the Microsoft Store with the account used to purchase the game and DLC.
🛠 Launch the Xbox and check the account is also the one used to purchase the game and DLC.
If the gamertags match, then the game and DLC will be listed. If they are not, sign into the Microsoft Store with the account used to purchase.
🛠 Update Microsoft Gaming Services
Check for updates to the Microsoft Gaming Services in the Downloads section of the Microsoft Store.
🛠 If you are using a VPN, disable it before downloading the DLC.
Test if the DLC downloads without VPN and you are able to launch the game. If the issue is resolved then you should be able to reenable VPN and play.
🛠 Check that the latest update has been downloaded
Microsoft Store: Update not showing in store – Age of Empires Support
🛠 Try the troubleshooting steps in the Xbox Support article below:
Troubleshooting downloadable content on Windows 10
🛠 Check that the computer is listed as a device used by the Microsoft Store.
Manage devices used with your Microsoft account
🛠 Check if the DLC is enabled in Steam.
To do this right click on the game in your Library and choose Properties. Then click on DLC in the list on the left and check that there is a check mark next to the DLC.
🛠 STEAM: Verify the integrity of the game files.
Follow the steps to verify the integrity of your game files. Once this is done, re-launch the game and verify that the issue is fixed.