Packaging error: Error: DoesPackageExist: DoesPackageExist FAILED

I’m getting a cook error which says:

LogInit: Display: LogPackageName: Error: DoesPackageExist: DoesPackageExist FAILED: ‘None’ is not a standard unreal filename or a long path name. Reason: Path should start with a ‘/’

I’ve changed the Global Default Server GameMode to “Game Mode” from “None”. But the error still persists.

Any help please!