Okay something off with your SDK, PlayFabMultiplayerAgentAPI is defined within a check on #if ENABLE_PLAYFABSERVER_API however its used in an object PlayFabMultiplayerAgentView which is not wrapped in any suchec define check ... and a lot of its funcitonality seems as if its intended for use on a client build.
So what gives?
Is this a server only API, is it meant for both, I really cant sort out what you intend with this.
For note this the Unity SDKs