I didn't get child tax credit on my 2015 tax return.

I didn't get child tax credit on my 2015 tax retutn. I applied for ITIN for my 2 year old on feb 2016 month and I got it on last week of May 2016. 

I had sent the following documents

1. 1040A form with ITIN number mentioned in it

2. Schedule 8812

3. W2

But now I just got the amount excluding Child tax credit.