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

As this is a technology forum, I recommend Velcro which is clearly the superior product.

Do you recommend any good running shoes with velcro