You do not say how old it is. Sometimes if they don't like the placement they are in there is little or no budding. Another way is to ensure they are fed and watered in July and August, so that they can make the buds for next years flowers. if it is dry then you would need to water it. I have one Camellia that was moved three times as a young plant before it bloomed. Now it is suited and blooming well, but it took time.

My first thought was the dry summer last year. The buds for this spring were forming then, and if it was too dry it would either be unable to make the buds to grow this year, or would drop them.

Have you pruned it? Camellias flower on older wood so pruning will cut off the flowering wood.