Just to clarify Josh’s debugging steps.
/UE4/Builds/PCmachinename/PCRootDir/UnrealEngine/Engine/Binaries/ has an xcode project in it that you open
Set scheme to IOSTest_RunIOS
Set destination to the iPhone that is plugged in
Product->Build For->Running (Option + Command + R, doesn’t seem to work on my PC keyboard)
Then Product->Scheme->Edit Scheme->Run IOSTest.app->Arguments tab
Put -filehostip=x.x.x.x into arguments passed on launch