As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) CREW HAD AN AVIONICS VENT FAULT ON THE GROUND. MTC WAS CALLED TO THE AIRCRAFT AND MEL 21-26-04 A WAS APPLIED. DURING THE CLIMB OUT, THE CREW REPORTED THAT THEY WERE UNABLE TO PRESSURIZE THE AIRCRAFT. AFTER DISCUSSING THE ISSUE WITH MOC AND DISPATCH.THE PLAN WAS TO LEVEL OFF AT 10,000FT AND DIVERT FOR MTC. RESOLUTION 24HQ CONNECTOR CLEANED. AEVC TEST CARRIED OUT, SERVICEABLE. (TC# 20190318006)