Q.My Crepe Myrtle Blooms Every Year, Except This Year. We’ve Had A Bad Drought But I Keep It Watered. What Could Be Wrong?
She has always been a late season bloomer but never failed to bloom before this year. I planted her between 10 and 12 years ago. This year before it started warming up, I cut back all the dead branches. The new growth has been amazing except there are no flowers.

Certified GKH Gardening Expert
Unfortunately, there are quite a few reasons why this won't happen. This article will help you to start figuring out what the, exact, cause will be:
https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/crepe-myrtle-not-blooming.htm