How to rotate a pawn

I use a third party library for networking. When a client connects to the server, a character and controller for representing the client on the server are spawned with

APlayerCharacter* NewPlayerCharacter = GetWorld()->SpawnActor<APlayerCharacter>(ACharacterBlueprint, Position, Rotation);
APlayerController* NewPlayerController = GetWorld()->SpawnActor<APlayerController>(APlayerController::StaticClass());
NewPlayerCharacter->Controller = NewPlayerController();
NewPlayerController->Possess(NewPlayerCharacter);

Then, in my custom PlayerCharacter script i receive keyboard input from the player and want to set the location and rotation. For location a use AddMovementInput(...);
This works fine. But setting the rotation does not work.
When i use AddControllerYawInput(...) on this newly created character on the server, nothing happens, althogh i made sure that the input that is received on the server matches the input that is send from the client, as AddControllerYawInput(...) works fine on the main character from the client.
I also tried Controller->SetConrolRotation(...) on the new character, but this didn’t work either.
So my quesiton is, am i missing something maybe already when spawning the character or something, or is there another way to rotate a character?