I have used Gmail SMTP service with port 587 on the local server and it's working fine.
But it's not working on AWS EC2 instance. So I added SMTP rules on EC2 instance security inbound rules see below image but SMTP port can not be editable.
Now the issue is if your domain does not configure secured connections. Gmail does not offer port 25 in an unsecured connection.
So, there is any way to use SMTP on unsecured connection with 25 port or any other way.
I have fixed issue as of now for a development server. Please, not it's not the correct way to a production site.
For sending an email from AWS EC2 using Gmail SMTP service please follow below steps.
you need to set your instance inbound rules for coming mail and outbound for send.
After that, you can send email using 587 SMTP port from AWS EC2.
Please read this article. https://support.google.com/accounts/answer/6010255?hl=en
https://myaccount.google.com/lesssecureapps