As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT, APU SHUT ITSELF DOWN ATTEMPTED RESTART AND FAULTED AGAIN. AIRCRAFT RETURNED TO BLOCKS (BTB). DEFERRED IAW MEL 29-11-1A CAT I PLAC INSTALLED MAINT. PRECED. C/W. A/C REMAINS NON-ETOPS. REF LP 39222-59/1. AIRCRAFT RETURNED TO SERVICE.