Error 3861, 3075, UBT error *.dll

Complete noob here so let me know what info I’m missing, thank you. I apologize in advance for lack of common sense.

Expected behaviour: Code compiling and me running over triggers to open/close door in Unreal.

Observed behaviour: Code doesn’t compile, can’t open the project in UE4.

Tried:

  1. retyping code
  2. Reinstalling, repairing VS and UE4
  3. Restarting PC
  4. Googling for a week without luck or running into things I have set up already

Here is a screenshot of the errors, but the first some are nonsense that sometimes appears and sometimes doesn’t, last 3 are consistent:

And here is the Build log:

1>------ Build started: Project: UE4, Configuration: BuiltWithUnrealBuildTool Win32 ------
2>------ Build started: Project: EscapeRoom, Configuration: Development_Editor x64 ------
2>Performing full C++ include scan (building a new target)
2>Using 'git status' to determine working set for adaptive non-unity build.
2>Creating makefile for EscapeRoomEditor (no existing makefile)
2>Parsing headers for EscapeRoomEditor
2>  Running UnrealHeaderTool "C:\Users\Marko\Documents\Unreal Projects\Section_03\EscapeRoom 4.18\EscapeRoom.uproject" "C:\Users\Marko\Documents\Unreal Projects\Section_03\EscapeRoom 4.18\Intermediate\Build\Win64\EscapeRoomEditor\Development\EscapeRoomEditor.uhtmanifest" -LogCmds="loginit warning, logexit warning, logdatabase error" -Unattended -WarningsAsErrors -installed
2>Reflection code generated for EscapeRoomEditor in 7.2237887 seconds
2>Performing 17 actions (4 in parallel)
2>[2/17] Resource PCLaunch.rc
2>[3/17] Resource ModuleVersionResource.rc.inl
2>SharedPCH.Engine.cpp
2>CloseDoor.gen.cpp
2>EscapeRoomGameModeBase.cpp
2>CloseDoor.cpp
2>EscapeRoom.cpp
2>C:\Users\Marko\Documents\Unreal Projects\Section_03\EscapeRoom 4.18\Source\EscapeRoom\CloseDoor.cpp(30): error C3861: 'GetOwner': identifier not found
2>MyCloseDoor.cpp
2>OpenDoor.cpp
2>EscapeRoom.init.gen.cpp
2>PositionReport.cpp
2>EscapeRoomGameModeBase.gen.cpp
2>MyCloseDoor.gen.cpp
2>OpenDoor.gen.cpp
2>PositionReport.gen.cpp
2>ERROR : UBT error : Failed to produce item: C:\Users\Marko\Documents\Unreal Projects\Section_03\EscapeRoom 4.18\Binaries\Win64\UE4Editor-EscapeRoom.dll
2>Total build time: 33.76 seconds (Local executor: 0.00 seconds)
2>C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\VC\VCTargets\Microsoft.MakeFile.Targets(44,5): error MSB3075: The command ""C:\Program Files\Epic Games\UE_4.18\Engine\Build\BatchFiles\Build.bat" EscapeRoomEditor Win64 Development "C:\Users\Marko\Documents\Unreal Projects\Section_03\EscapeRoom 4.18\EscapeRoom.uproject" -waitmutex" exited with code 5. Please verify that you have sufficient rights to run this command.
2>Done building project "EscapeRoom.vcxproj" -- FAILED.
========== Build: 1 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Solved it by reverting to older code, downloading the version of UE4 4.17.2, deleting saved, intermediate and binaries and rebuilding it.