DFPlayer stand-alone with trigger not switch FAIL …

Hi, I’ve bought a few DFPlayers to play with and it’s fantastic how easy it it to get started with, within a couple of mins I was happily tapping IO2 to ground simple … then I tried to replace the push button with a n-channel mo that I was pulsing ‘on’ with a very short pulse … IO2 is connected to the drain and the source is going to GND,  the mosfet is switching fine,  and ideas as to why using a mosfet (I’ve tried NPN BJTs and even a relay) what have I stupidly not considered?

many thanks in anticipation …

Pete