NVR DS-7608NI-M2/8P POE not powering more than 4 cameras

[mbailey]

I have just setup a DS-7608NI-M2/8P to have 5 x DS-2CD1383G2-LIU cameras connected to the POE ports on the NVR. The 1st 4 work fine but when I plug the 5th in there is no power sent to the camera. If I unplug port 1 then the 5th camera powers up. All ports have PO enabled. I can plug 4 cameras into any combination of ports and they work but Amy more than 4 and they don't power up. It is as if the NVR only has enough power for 4 cameras. The NVR is showing 10 watts in use of 120 so I can't understand why this is. I am hoping someone on here can help?