Child Credit & stimulus bill

My son was born in August of 2019 and we filed our takes in early February 2020. We marked him down as a dependent but I noticed I never got the child tax credit. It marked him as "credit for other dependents" even though it says his relationship is "son".  Is this because he was only alive for 4 months in 2019? 

Then the stimulus bill came in and we didnt get credit for him either (less $500). Why are we not getting credit for him in 2019?