Same like my LO. Once he starts to eat solids, his milk intake drops a lot. I’ve actually asked a PD about this. According to PD, it’s okay if they reject milk. Some babies prefer solids. His advice is to include more calcium into the solid food. Like ikan bills. Or u can try giving him lesser milk but more often? Like instead of 150ml 4 times a day, try 100ml, 5 times a day? Sometimes I offer my baby milk with his snacks such as biscuits and puffs. After eating these, normally he’ll be thirsty, then I offer milk. In IFC, the Teachers will let him drink from a straw instead. Apparently, he will drink the milk from straw but not from the usual milk bottle. But this method doesn’t work when I try it at home 😂. You can also try spoon feeding him the milk. It will take forever to finish the milk, but at least he’s drinking it I guess.
Can try giving him snacks, biscuits to substitute for the milk, maybe he's teething, else try to change to other brand of formula milk (: