Not drinking milk

I need help from mummies out here. My 2month LO doesn't want to drink his milk. He is on fully formula milk. Once i put the bottle in his mouth he will keep on crying and pushing his tougue out. I will need to comfort him and once he is in sleepy mode then he would suck the bottle n drink. There is no oral thrush n no fever. If we nvr fed him he is ok can smile. Change bottle change teat also the same.Any mummies experience these? How long will these last?