When reviewing video, it starts and then says no data

My hardwired floodcam(s) are recording video, but when I review it a second time or even the first time, it starts and then says no data. Sometimes I have seen it the first time, and when I review it to download it, no data comes up. This is not happening to just one floodcam but several. I am running T1 line, so that is not the issue. I reinstalled all the cameras, and this still is an issue. This is not good as I am using my cameras as security and need these videos. Anyone help???