As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: EMERGENCY LIGHT TEST FAILED EPSU COMM AFT L MESSAGE SHOWN. **SUPPLEMENTAL REPORT FOR AALA202110191671: REPLACED THE AFT EMERGENCY POWER SUPPLY INIT AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK PER AMM 33-51-38** (CLOSED)