I recently setup a few new cameras on my BlueIris box, however one camera in particular was giving me problems. I tried a few different configurations and each time I got a no signal error. I could change the IP to another camera and all was well, but this one in particular was angry at me. I could log into the web interface and view the feeds, so I knew it was working, it just had something up in the configuration. I ended up looking at the Blue Iris status UI to see that I was getting about 1.5FPS through with a slightly lower bitrate than the camera was configured to at the time. I updated the camera config to drop the bitrate and voila, signal, smooth video.
The root cause is something in the cable, either too much interference from AC wiring, or an end isn’t as well crimped as it could be. Either way, I got my camera up in my Blue Iris instance and things worked fine after that.