Fatal error on DCS1800z

Hello.

I recently took over a store with a DCS1800z f6t UV printer being used for direct to garment printing. When I took over the printer was not functioning, however I was able to get it printing with a little troubleshooting and research.

Now intermittently the printer will give a fatal error, code 51H (CR unlock confirmation error) - Paper jam, foreign object, deformation of the main frame

Does anybody have any info on where I might start troubleshooting and diagnosing this problem? There doesn't seem to be a pattern to when the machine decides to throw the error, we can print multiple runs, only to have it fail randomly. Any info, even just a direction to start looking would be greatly appreciated.