faulty Camera or HDD

Hi Guys. I am a complete newbie to CCTV but have recently had a camera install - 6 cameras all external 4MP and in general am happy with the setup.

1 camera though is playing silly and despite me calling the installer they haven't rectified as yet. I will, if it is deemed necessary get tough with the installer but thought i maybe able to get help here first.

I have attached a file which shows the playback for 3 cameras for several hours... as you can see 1 camera is shutting down intermittently throughout the file. The camera has been re wired from the HDD to the box, and also I have moved the Ethernet lan channel for the camera. The re wire did nothing IMO but the Ethernet switch seems to have resulted in reduced disconnections. Previously the HDD alarm would sound for 1-2-5 hours at a time, now it doesn't do this, but obviously there is still an issue. When the camera shuts down it loses its IP within the network. I am viewing on Vision HDD via IE or on XIQ app on IOS

A switchout of the camera would be my thought but I don't think the HDD (X2R8N) playback should show as it does anyway and maybe its the POE causing issues?

Cameras are Xvision HD IP 4MP.

Anybody have any clues?

Set the cameras to have a static IP as it sounds like you have them setup for DHCP.

The camera might not be getting proper power and therefore randomly shutting down and starting back up.

If your using PoE sometimes putting the injector closer solves the problem as some injectors can't handle 100ft of ethernet I've learned (this also includes crap/cheap ethernet cable).

EDIT: Even PoE injectors that say they can handle 300 ft I've had problems with.