First, please make sure the holster you have is an approved fit for your pistol (see on this page the question concerning gun fits).
If your holster is from our standard series (no retention adjustment screw), it might need a 'break in' period. Draw fast and decisively, in an upwards motion, in line with the holster direction. Do it many times, until you feel the draw is easy enough and not too much force needs to be applied. You may also apply some silicone (or similar) spray inside the holster, in the trigger guard area, to ease the draw. You may watch this YouTube video for further guidance:
If your holster is from our ND series (with retention adjustment screw), simply try to unscrew the retention adjustment screw up to the point where the draw is convenient and not too difficult when drawing in a fast and decisive upwards motion. In any case, do not completely unscrew the retention adjustment screw.