As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN ALTITUDE CAUTION MESSAGE COMPLIED WITH QRH. ECS PAGE ALL GREEN LINES FLASHING. AT 21000 FT IT APPEARED THAT PRESSURATION STARTED WORKING AGAIN. ENROUTE TO SWF ACFT DIVERTED, EMERGENCY DECLARED AS A PRECAUTION. R & R NR1 SAFETY VALVE IAW AMM 21-32-03. OPS CHECKED GOOD. NO FAULTS NOTED AT THIS TIME.