As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FLIGHT LEVEL 290 LOUD RUMBLE FOLLOWED BY RAPID RISE IN CABIN ALT. BOTH OUTFLOW VALVES CLOSED AND FLT LEVEL 220, CABIN STILL CLIMBING SLOWLY. DESCENDED TO 10,000 FT TO MAINTAIN PRESS. FOUND FWD CARGO DOOR SEAL DAMAGE AND OUT OF RETAINER. REPLACED DOOR SEAL AND CABIN PRESS NORMAL.