How can we unblock Port 25 outbound in EC2?

I have started using EC2 recently and am trying the services provided. Unfortunately, I found that port 25 outbound blocked. In my use case, I am not sending any emails however I check new users' email and verify it's existence. In order to verify the email address we need port 25 unblocked. We don't send emails actually but just check the mx records connection to confirm whether mx record is valid or not. And for this, only one port 25 outbound is necessary with no alternative.