There is a ratching sprocket below the collet shaft, it maybe broken or the key that engages the ratchet, either is a easy fix and the parts are inexpensive. After disconnecting the power a 15 torx screwdriver will remove the cover, which will give you access to the space, there may be a piece of debris causing the problem, at least you will have the ability to see what is going on with your router. There is an exploded drawing in your instructions that will guide you. Hopefully it's just debris and you can route away after you clear it out, if not and you are still covered put the cover and screws back together and send it in, if you're out of warranty it's a easy fix, the parts just drop in.