Cameras dropping out

I have had the 4mp system for about 8 months and have enjoyed the system except for one nagging problem. I have 7 4mp cameras setup with to a patchblock in an attic, then ran to the NVR in a closet. The NVR does not appear to be over heating and they stream just fine. But every once and awhile a camera drops out and does not reconnect. The NVR acts like the camera is gone, but the camera is still getting power. If I pull the cat wire out of the NVR or the patch block the NVR sees the camera and it reconnects without issue. This is so frustrating because I can’t seem to find a rhyme or a reason for why it’s happening. Anyone have any ideas?