I would suggest switching loglevel down to "debug" or even "info" so that we can see the bigger picture. I would then save a copy of the log and delete the content of the original to get everything nice and clear.
Restart the server and try to reproduce the error. You imply the error is intermittent which is going to be tricky.
My first guess is that the drivers are the issue. Did you install the printer from the CUPS web interface (
http://localhost:631)? How did that go?
Things to try:
Reinstall the printer on the server.
Reinstall the printer on the client.
See what the log says.
Try to print something.
I am a SuSE user so I am unsure what the implications of Fedora Core are. I was not happy with the SuSE ghostscript implementation and my system works well with ESP Ghostscript: the CUPS people own implementation of ghostscript which is supposed to be strong on drivers. I am using 8.15.1. See what the log says, but it may be a way forward when you have tried other things first.
Good luck.