Probably nothing but impatience.. Okra buds last a while before opening. Where are you that you have okra this time of year? I don't see any insect damage, Here Leaf Footed bugs will some damage the buds.

Agree with Farmerdill. The buds visible are not yet fully grown, and should begin to open in a few days. There are aphids visible on the buds though, you might want to keep an eye on them, in case their numbers grow.

Thank you. I didn't know the buds take sometime to open. Im in Malaysia though. We have tropical climate here so the temperature remains above 25Celcius all year. I planted this okra on January 28.