As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STARTED RIGHT ENGINE DURING TAXI . GOT 2 HUNG STARTS. N 2 MAX WAS 40. QRC DID NOT FIX IT(APU AIR DUCT PRESS LOW) AC RETURNED TO GATE (BTB) AND MTX GROUNDED AC .AND DEFERRED APU AIR FOR DEPARTURE IAW ABX-49-11-1-1 .AND RETURNED AC TO SERVICE.