Go to the BP_SGKInventoryInterface and copy the video below.

Next go to the location shown below and add the highlighted nodes, location at top of image.

Next go to the BP_SGKController and then to the BeginPlay collapsed node and create a new custom event called ServerUpdateCharacterYaw and set it to RunOnServer and tick Reliable. Then add an input called Pawn and set its variable type to Pawn.

Next copy the image below adding the highlighted nodes.