What was found
AFTER TAKEOFF AIRCRAFT WOULD NOT PRESSURIZE, AUTOFAIL LIGHT ILLUMINATED AND FAILURE TO PRESSURIZE. AFTER TAKEOFF ABNORMAL PROCEDURES WERE COMPLETED. THIS DID NOT RESTORE NORMAL CABIN PRESSURIZATION. A LOUD NOISE WAS COMING FROM THE FORWARD ENTRY DOOR AIRCRAFT AT 1200 FEET HAD 1.2 DIF. WITH CABIN AT 9000 FEET DURING INSPECTION A GAP WAS AT REAR OF DOOR BUT THE S/O DOOR ANNUNICIATOR DID NOT ILLUMINATE AT ANY TIME. FOUND FWD ENTRY DOOR NOT SHUT PROPERLY. CLOSED ENTRY DOOR, PRESSURIZED AIRCRAF. OPS GOOD IAW 52-11-01 AND 21-31-0.