If your air handler is leaking condensation, this normally relates to three potential issues:
1.) Your mini-split can simply be low on refrigerant and cause the lines to sweat and start dripping water.
2.) Your air handler could of been installed in a angle, which causes the condensation to accumulate and eventually start dripping.
3.) Lastly would be a loose connections between the drain pan and the drain pipe or a leak in the pan itself.