Open your .uproject file in a text editor or IDE and check that your C++ modules are listed in the modules variable. The top of the file should look something like this:
{
“FileVersion”: 3,
“EngineAssociation”: “5.4”,
“Category”: “”,
“Description”: “”,
“Modules”: [
** {**
** “Name”: “GameTitle”,**
** “Type”: “Runtime”,**
** “LoadingPhase”: “Default”,**
** “AdditionalDependencies”: [**
** “Niagara”,**
** “Engine”,**
** “CoreUObject”**
** ]**
** },**
** {**
** “Name”: “GameTitleEditor”,**
** “Type”: “Editor”,**
** “LoadingPhase”: “Default”,**
** “AdditionalDependencies”: [**
** “Niagara”,**
** “Engine”,**
** “CoreUObject”**
** ]**
** }**
** ],**
“Plugins”: [… etc.