Are you sure you operated it right?
Sorry for asking-but sometimes it´s just "finger troubles"…
The system had a "1 or 2" flight director mode-for each pilot?
Was it operating in the right mode (e.g. "2" if you were flying from the right seat)?
The ATT itself doesn´t do much-it just "freezes" the stick, and is supposed to maintain the aircraft attitude….only the operating modes (ALT, VS, IAS, HDG…..) will do the "work"….