Cavities after braces

I got my first cavity on my adult teeth after getting my braces off a few years back. Now, its been about 4 years since I've gotten them off and I always have cavities when I go to the dentist. I kept pretty decent hygiene with my braces, maybe only once did they tell me to work on it and then after that they said I was doing good.

Even now, I keep good hygiene. I believe I may have some now in the shape of my braces bracket, since there is a yellowish spot indented in part of the outline of the bracket.

What is causing all the cavities so many years later?

edit: spelling