Okay, i dont know if this might help, but one way i found out whats going on with my project is to try un checked all maps that i want to cook. And then try to package the maps one by one. From here, we can narrow down what is exactly the problem.
In my case, first i have to unselect all the cooked files. From there, i know that my files are correct, and have no error. If it does showing some error, you can try delete the “config, intermediate, and saved” folder in your directory
(CAUTION!, Doing this will delete all your saved project settings like, inputs, folder colors, and more. The rest i still havent discovered, but most importantly, your inputs will be deleted. Do this with cautionary!)
If you can packaged your game correctly, then nothing is wrong with your files. Now, select your cooked files one by one. In my case, i have to select one of my maps, then packaged it to check if there any error. After doing this with all my maps, turns out, one of my map has a problem. So i decided to make a new map. And packaged it.
After that, i start to put all my actors one by one, and packaged it after each placed actor. This way, we can determined what blueprints have a problem. And this really helps me, turns out two of my bp have error in it. The only problem from here… I dont know what is wrong with it. Theres no error whatsoever on the bp, or when i play the game. Everything is fine…
Hopefully this helps, if you have something to suggest or anything, please do!