What was found
JAX - FLT 0364 - CABIN PRESSURE WAS LOST AT FL290 & OXYGEN MASKS DEPLOYED. CREW SWITCHED FROM AUTO TO STANDBY TO MANUAL, BUT CABIN PRESS COULD NOT BE CONTROLLED. BLEEDS WERE SWITCHED, BUT CABIN STILL WOULD NOT PRESS. ACFT DIVERTED TO JAX. MX FOUND AFT CARGO DOOR SEALANT MISSING BETWEEN SEAL CHANNEL & FUSELAGE AT LOWER FWD & AFT SECTION OF DOOR FRAME. AREA RESEALED USING AERODYNAMIC SEALANT, DECAY CHECK PEFORMED PER MM 5-51-101 & SYSTEM CHECKS GOOD. IN ADDITION, CABIN PRESS CONTROLLER REMOVED & REPLACED AS A PRECAUTIONARY MEASURE. MX FOUND ALL OXYGEN MASKS HAD DROPPED FROM THEIR PSU'S. ALL OXYGEN MASKS WERE CLEANED & STOWED. (X)