Thank you so much. ?Your incoming transition needs to last long enough, and be strong enough, to shut Off Q2, and turn On Q1 so it conducts. Then current is drawn through C2, to start the timing sequence.
Try different values for C1. Because too small a value conveys a weak pulse. (1 pF is a tiny value.)
Also try different places to connect the activating pulse. Also try a falling transition as well as a rising transition.