Today, when my teammates are trying to build the project, they got quite a number of errors when trying to do so but the project compiled and ran well in the editor. Since I was the one who worked mostly on C++ files, my errors are clear by doing the FORCEINLINE functions fix mentioned in the "FORCEINLINE functions" entry.
However, on their side, they couldn't get it built. One of my teammates recalled my lecturer saying that the database ( .db) file is generated when we compile and build the project and he suspected it is the .db file which is causing this mysterious error. He proceeded to delete the database file and the problem was fixed. This proved that database file will mess with the way Unreal build the game so, it must be deleted before building the project.
TL;DR
Always delete database ( .db) file before building the project.