What Causes Formula Feed And Drinking Water Refusal?

Hello doctor.. My daughter completed 10 months this 6th.. She used to drink (70 to 90 ml per feed) her formula 4 times a day. I give her formula when she naps in day/sleeps at night. Suddenly she stopped drinking all of a sudden totally. She loved water.. Even refuses that now. Not any new teething... Herurine amount is lesser than normal...