Dying Buds

[Blooming Idiot]

I have repeatedly had my adopted orchid get a stem full of buds. The first couple will bloom but the others die before they open. The plant and leaves look otherwise healthy. I water it about once/week. It gets indirect sunlight. I've included a pic that shows healthy blooms and dead buds circled. Sometimes the buds are about to open when they die. Other times they are very small. Thanks for your help.