Ue4 Game Wont Package! "Missing UE4Game Binary"

We are desperately trying to package our Ue4 game at 64. It persistently wont work, while I have no such issue for any of my other projects.

We get this error:

Missing UE4Game binary.
You may have to build the UE4 project with your IDE. Alternatively, build using UnrealBuildTool with the commandline:

No clue what it means. It wont build on anyone’s PC.

If it helps, we aren’t using any C++. Purely blueprints. Is a simple project with one map.
Need it packaged as a dev build by 2 days.

Any suggestions?

I’m having the same issue, did you ever figure this out?