My 9 month old all of a sudden is fighting naps… what do I do?

How to get my 9 month old to nap?! All of a sudden he has been fighting his morning nap (roughly 3 hours since slept) and now today fighting his afternoon nap also and it’s been 5 hours since he has slept. He only slept 30 mins this afternoon when it’s atleast close to 2 hours now that he stopped his morning nap. Why is he now fighting his afternoon nap too. Idk what to do help