As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THIRTY MINUTES INTO FLIGHT AT FL 350 OXYGEN QTY INDICATES ZERO. ALL OXYGEN REGULATORS WERE IN EMERGENCY-OFF POSITION. PERFORMED LEAK CHECK OF OXYGEN LINES IN E&E BAY, NO LEAKS. CHECKED ALL MASKS AT REGULATORS IN COCKPIT, CHECK OK. REPLACED BOTH OXYGEN BOTTLES, O2 PRESSURE 1900 PSI. PERFORMED LEAK CHECK. NO LOSS OF PRESSURE. OK TO CONTINUE.