I have a porcelain crown that keeps coming off. What should my dentist be doing !

I have a porcelain crown that keeps coming off. What should my dentist be doing to correct?

I doint chew sticky foods or hard foods. I was flossing when it popped off into the sink.

Maybe the remaining tooth structure inside is very little,might need a post to reinforce it well. (Place post,then core build-up,take another impression,then new crown)

Or maybe, the crown is too high(meaning its touching the opposing tooth when you bite)causing the crown to be dislodged when you bite hard. (Solution:Check the occlusion and reduce whatever needs to be reduce on the crown)

Or maybe,it's with the cement (maybe too long mixing time,or the material hasn't completely set when you eat or the material had set right away)

Or there could be leak causing water,food to get inside.(Change your crown)