Unfortunately it's hard to tell from the photos what is causing these symptoms, but sometimes aborted flowers (those that fail to open or which die soon after opening) are caused by environmental stress, insects, or infection. In the case of insects, thrips are often responsible, and they can be small and hard to see, especially in yellow or dark blooms since the insects are often yellow or black, or in blooms which never open, because the thrips are tucked into the bundled flower parts. If you peel open several of the buds, look for yellow rice-shaped tiny insects (the thrips). While they can also be common in normal flowers, so their presence isn't a guarantee that they were responsible, if numerous, that might indicate the source of the problem. Infections that cause "bud blast" (another term for unopened flowers) may be due to Botrytis (also called gray mold), which despite its name, won't necessarily have much in the way of visible moldy growth on the outside of the flower when the weather is dry.

The only recourse for both thrips and Botrytis is to remove the affected flowers by clipping them off. (Dispose of them rather than putting them into a compost pile.) No insecticide or fungicide is recommended (or effective, in this situation). If it was due at least in part to moisture stress, feel the soil around four inches deep (for in-ground plants) or a couple inches (for potted plants) to determine when it's somewhat dry to the touch; at that point, a thorough watering may help the plant avoid more bud blast.

Miri