#include “Engine/NavigationObjectBase.h”
#include “GameFramework/PlayerStart.h”
Though Im not sure if there are not header files that include more from a module and the needed dependend headers.
Rama has an update thread somewhere here on the forum that has better infos then me.
Edit: Same issue on AnswerHub was answered by an engine developer to do the same as I suggest above, include the NavigationObjectBase.h file before PlayerStart.h