You need to make sure your knot is a proper (double-slipped) reef knot, and not the granny knot. It's easy to mix them up, and keep doing a granny knot by habit

You need to make sure your knot is a proper (double-slipped) reef knot, and not the granny knot. It's easy to mix them up, and keep doing a granny knot by habit. https://www.fieggen.com/shoelace/grannyknot.htm https://www.fieggen.com/shoelace/grannyknot.htm