Hi there !
Camera problem here ! 
Camera model Raspberry Pi camera off Aliexpress
What is the problem? Last year, my camera started failing; had trouble getting an image, sometimes i had no problem, sometimes the image never appeard.
My raspberry was in basement, so poor wireless connection, and thus i blamed it for the lack of image.
I unplugged it, waiting to sort things of.
Few months later, i bought a CPL, set everything up and tried again. No image.
Unplug, clean, re-plug; No image.
Format and fresh install of Octoprint; No image.
Image can't be seen from control panel, no snapshot either, so ... it appears my camera's dead.
But it's weird, there is no reason ? Appart from natural death, but it's weird she was working on and off before dying ?
Anyway ! I'd like to be sure, before buying another one and getting the same issue 
What did you already try to solve it?
Unplug, replug, clean connectors, fresh octoprint install
Logs (/var/log/webcamd.log, syslog, dmesg, ... no logs, no support)
Meh ? New users can't only put 2 links in the topic ... So i'm not able to post my log 
Additional information about your setup (OctoPrint version, OctoPi version, ...)
Thanks for your help guys !
Cheers from Belgium