Water it! Best water is clean or filtered, or solarized, or rain water. Water
in between layers. if pile dries out then cover with a trap. Be careful not to over water.
without water the pile will not cook up. A good idea is to use a sprinkler can that the
water has been allowed to sit over night in. Add a little seaweed (or
or fish emulsion to increase bacterial activity.
is good for this too.
It is also possible that the compost pile is getting too hot and drying out. Just becarful with your mixtures.