It's a little unclear... did the embryos fail to thaw, or fail to grow to blast?
I've had bad results at both - from a total of 35 eggs (over two cycles) I've had only 11 get to blastocyst. Of those 11, all were frozen and only 4 of them ever thawed.
My clinic put it down to a very particular reason - I have PCOS and had hyperstimulated (with 26 and 32 eggs collected each time!) with both cycles and their solution was to not get OHSS next time... Difficult, but it worked.
Sometimes they just don't have a reason for things failing to progress or failing to thaw. There's a lot still unknown in the science of ART.
I hope you have much better luck next time.
BW