This error usually means that your game is in the process of being updated. Once the update is released and downloaded you should be able to launch the game without any problems.
Restarting the launcher refreshes the entitlements on your Epic Games account and may trigger a required game update.
If restarting the Epic Games Launcher doesn’t fix the issue, try verifying the game files.
Verifying your game files ensures your game is installed and updated properly. To verify your game files:
Depending on the size of the game, this process may take a while. Once it’s done, relaunch your game.