Hi Reydel,
Thank you for using the Xerox forum.
Your issue seems somewhat strange since rebooting clears the problem, not clearing or loading paper. Is the paper being used a standard size and is that same size displayed on the user console?
I would suggest that you review the following solutions.
Constant or Repeated Jams http://www.support.xerox.com/support/WC780X/support/en_US.html?objGUID=16876
If these do not resolve your issue you may consider Contact an experienced service technician at the following link:
Hi i got a 7835 ,everytime we reload tray 4 its saids ,check door c for jam ,i check door c nothing there ,once i open in close door c ,it saids mis fed paper in tray 4 ,this happens everytime tray 4 has been open ,only way to remove error is reboot machine,i check paper setting,they are correct,please help asap