As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW NOTED DURING CLIMB OUT THAT COULD NOT PRESSURIZE A/C AND NO WARNING INDICATION, THEY RETURNED TO BNA FOR MTX. AFTER LANDING FOUND THE AFT CARGO DOOR AFT SECTION WAS NOT CLOSED ALL THE WAY. RESECURED CARGO DOOR PERFORMED GVI OF CARGO DOOR AND PERFORMED. OPS CHECK OF DOOR IAW CRJ MM 52-31-00, OPS CHECK GOOD. NO DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.