Amazon EC2 ssh connection time out

I cannot connect to my instance via SSH. I followed the steps in the document but no luck.

I tried this way:

ssh -i mykeypairname.pem ec2-user@52.74.224.84

And it shows notice:

ssh: connect to host 52.74.224.84 port 22: Connection timed out

I'm sure that I've opened port 22 for all IP (see the attachment)

Please give me a solution.