I added the above files and still error, Here is the error i am getting.
Colored for easier reading.
1>FUUnrealCharacter.gen.cpp.obj : warning LNK4006: "public: void __cdecl AFUUnrealCharacter::ServerIsSprinting(bool)" (?ServerIsSprinting@AFUUnrealCharacter@@QEAAX_N@Z) already defined in FUUnrealCharacter.cpp.obj; second definition ignored
1> Creating library C:\Users\********\Documents\Unreal Projects\FUUnreal\Intermediate\Build\Win64\UE4Editor\Development\FUUnreal\UE4Editor-FUUnreal.lib and object C:\Users\********\Documents\Unreal Projects\FUUnreal\Intermediate\Build\Win64\UE4Editor\Development\FUUnreal\UE4Editor-FUUnreal.exp
1> [32/33] UE4Editor-FUUnreal.dll
1>FUUnrealCharacter.gen.cpp.obj : error LNK2005: "public: void __cdecl AFUUnrealCharacter::ServerIsSprinting(bool)" (?ServerIsSprinting@AFUUnrealCharacter@@QEAAX_N@Z) already defined in FUUnrealCharacter.cpp.obj
1> Creating library C:\Users\********\Documents\Unreal Projects\FUUnreal\Intermediate\Build\Win64\UE4Editor\Development\FUUnreal\UE4Editor-FUUnreal.suppressed.lib and object C:\Users\********\Documents\Unreal Projects\FUUnreal\Intermediate\Build\Win64\UE4Editor\Development\FUUnreal\UE4Editor-FUUnreal.suppressed.exp
1>FUUnrealCharacter.cpp.obj : error LNK2001: unresolved external symbol "public: virtual void __cdecl AFUUnrealCharacter::ServerIsSprinting_Implementation(bool)" (?ServerIsSprinting_Implementation@AFUUnrealCharacter@@UEAAX_N@Z)
1>FUUnrealCharacter.gen.cpp.obj : error LNK2001: unresolved external symbol "public: virtual void __cdecl AFUUnrealCharacter::ServerIsSprinting_Implementation(bool)" (?ServerIsSprinting_Implementation@AFUUnrealCharacter@@UEAAX_N@Z)
1>C:\Users\********\Documents\Unreal Projects\FUUnreal\Binaries\Win64\UE4Editor-FUUnreal.dll : fatal error LNK1120: 1 unresolved externals
1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\VC\VCTargets\Microsoft.MakeFile.Targets(49,5): error MSB3073: The command ""C:\Program Files\Epic Games\UE_4.25\Engine\Build\BatchFiles\Rebuild.bat" FUUnrealEditor Win64 Development -Project="C:\Users\********\Documents\Unreal Projects\FUUnreal\FUUnreal.uproject" -WaitMutex -FromMsBuild" exited with code -1.
1>Done building project "FUUnreal.vcxproj" -- FAILED.
If i take the Reliable, Server OUT it will compile. I can leave this in UFUNCTION() it will compile fine.
Same thing goes for UPROPERTY(Replicated).