I have several epis. All are blooming each spring. One in particular, the largest of the plants, gets many flower blossoms. However most of the blossoms grow a bit and then fall off. Some survive and blossom beautifully. This does not happen with any of the other epis. All of the plants are kept on a semi heated porch kept at a minimum of 55 degrees. It's not a pest problem, no bugs, no aphids. I water starting in February with an orchid fertilizer, then stop after flowering between May and July. The other successful epis are just starting to bud out now and will not drop any buds. The problem child has been growing buds for several weeks already. Is it a temperature thing? Is this variety more sensitive than the others and needs to be kept at a warmer temp?

EdinNY, I have found that cooler shade when in bud is the best for them. Have you thought about dividing this one? It appears that its way overcrowded. Ours here
don't bloom until it warms up and we give them very little fertilizer. Best to neglect them and min water.

I had half a dozen plants from my mom for years without them ever blooming. Then one year I tried the orchid fertilizer in spring and they've all bloomed ever since. The blossoms surviving are the ones closest to the window and getting the most sun and warmth. Both these things seem contrary to the normally accepted advice. I guess I'll just have to keep experimenting! Thanks for your reply. Perhaps dividing the plant might be a good idea if the roots need more room to soak up nutrients that can support a lot of blossoms.

I can't see anything wrong with your set up.
Plant looks healthy, pot looks like a good size.
The blooms are lovely and look large,(any idea what epi it is?).
Some hybrids do have a habit of dropping buds, I would say that may be one of them.
Bear in mind a slightly root bound plant is a plus for blooms.
Most growers apply a bloom booster when buds are developing.
One thing that can make buds drop is moving it around so the light comes from different directions.
Good luck!