Did you just get it? I would not be worried they tend to come out at night or early morning for me. As long as the coral does not look like it's receding or rotting I would not get worried.
If it is still puffy and filled out, then it is probably just full of sunlight, and does not need the food. Also, some corals need to be introduced to the "smell" of the food, and then they start feeding by extending a couple mins later.