As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAIN CABIN DOOR WILL NOT OPEN FROM INSIDE OR OUTSIDE. USED AFT EMERGENCY EXIT TO DEPLANE. GAINED ACCESS TO INSIDE OF CABIN DOOR & REMOVED A LOOSE SCREW THAT WAS JAMMED INSIDE AFT SIDE MIDDLE DOOR LOCKING PIN SOCKET. CLOSED ALL DOOR ACCESS PANELS & REINSTALLED STEPS. OPS CHECK MAIN CABIN DOOR LOCKING/UNLOCKING MECHANISM GOOD PER CE560XL MM 52-10-01.