Not relevant in this case since it is strictly speaking not a camera specific issue.
What is the problem?
When you configure octoprint to use a given url for web camera streaming the test works just fine but when you later go to the web camera it doesn't work.
The reason for this is that octoprint at the end of the url adds a question mark then a bunch of numbers.
In my case this will always result in a "404 not found" from the camera stream (separate pi zero dedicated to camera only)
So url must not end with things like: ?1589746181259
How do i convince octoprint not to add this?
What did you already try to solve it?
/var/log/webcamd.log, syslog, dmesg, ... no logs, no support)
Additional information about your setup (OctoPrint version, OctoPi version, ...)