As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CAPT LOST PRESSURIZATION, MANUAL MODE WAS WORKING. THE AIRCRAFT RETURNED TO IAH AND LANDED WITHOUT INCIDENT. MAINTENANCE PERFORMED A OPERATIONAL CHECK OF THE PRESSURIZATION SYSTEM, NO DEFECTS NOTED. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.