As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON GEAR UP RECEIVED NOSE GEAR /DOOR RED WARNING MESSAGE, ALSO A CAUTION HYD 3A LOW PRESS MESSAGE ON FOURTH ATTEMPT. QRH COMPLIED WITH, GEAR CAME UP AND LOCKED UNDER NORMAL CONDITIONS GEAR UP TOOK APPROX 15-20 SEC. A/C RETURNED TO ATL AFTER T/O (EMERGENCY DECLARED).