If you are using the HDMI-to-VGA adapter, ensure the HDMI cable is securely connected to ScreenBeam receiver and VGA cable is securely connected to the VGA adapter.
Some legacy projectors use a different video format than the default format used by the ScreenBeam receiver. Enter the local management GUI and set the VGA Compatibility Mode option to either 1080 or 720.
The projector may be set for the wrong type of incoming signal. The purple hue that is seen can be caused by viewing an analog RGB signal in the YPbPr or component video mode. Change the Projector's Signal Input to either "Auto" or "Analog RGB".