Unable to send mail from Laravel Project through SMTP on AWS

I'm using Laravel inbuilt Mail helper for sending mail. It's working fine on my local system. But when trying to send mail on AWS EC2 server, I'm getting server error 500.

I've tried connecting through port 25, 587 both. I've tried using gmail and postfix server for sending mail. Both are working fine on the local machine as well as digital ocean VPS but not on AWS instance.

via Chebli Mohamed