How to setup Camera Motor

Overview

Using a Game Creator camera motor for a Multiplayer doesn't work the same way as a Single player game and the reason for this is that depending on the type of camera you use like Adventure or First Person these types of camera requires a target and usually you use Player as target
The problem is the Player instance doesn't exists yet therefore you will get errors.

Solutions

For all the possible solutions you can have 2 separate Camera Motors one that will be active at the beginning looking at your map for example and another one for the player that should be inactive.

Use a Variable

Inside the Photo Instantiate action there is a Assign To Variable field which you can use to store your player instance.
Once your player is instantiated this variable will change therefore you could use a On Variable Change
Once your player becomes active you can turn on your player camera and call the change Camera action.
In this example we choose to set Player Camera target to be the same variable we use to store our player Instance. If you choose to use Player instead of a variable as target you must have this game object turned off at the beginning.