Perhaps it wasn't as noticeable until it dried.
It may be the kittens is a weak suckler. May even have a hole in the roof of mouth (palate). Such kittens can often be saved by giving them food by a syringe as mentioned earlier. With a syringe they dont need to suckle, its enough they manage to swallow.
I believe it has been about 7 hours since it fed and another 4-5 hours before it ate before that, note that these feeding sessions are only about 2-3 minutes long at most. It is still strong enough to crawl around the room it just refuses to suckle. The Kitten was moved by Midnight ( I believe she dislikes the floor heater which could be part of the issue but she moved it to the other side of the room). I do not own a microwave would a hot water bottle wrapped in a blanket suffice?
Good news! We can downgrade the red alert into yellow alert. but you must continue vigorously with the good work.
It started feeding with its mother but I have to supervise because she keeps moving it to a corner near the outside wall of our house... since its so far north it is -20 or colder outside so all the outside walls are to cold for a kitten. So every time she feeds the kitten I have to move it back to the nest we made it so it can warm up. I will continue to feed it with a syringe in addition to make sure it gets what it needs. Instead of the floor heater we put a blanket on top of a hot water bottle in a circle formation to make a nest for it to sleep in. Since the mother will only pay attention to it when i bring it to her she then moves it to the corner that is to cold feeds it and I move it back to our makeshift nest and feed it with a syringe to make sure it has enough. The procedure is tedious but the kitten seems much happier so I can only assume it is working.