WordPress amazon ec2 contact form. How right?

Question

Amazon Web Services

Preface.
I have a WordPress site hosted on amazon ec2 (ubuntu).
Form layout is ready.
What did you do.
Started with plugins. I tried contact form 7. It didn't fit through the layout of the form itself. (Although later I returned to this decision, but more on that later)
Then I tried to connect php that would send letters. I found several options on the net, but none of them worked.
There was an idea to put contact form 7 and try to at least achieve the result with sending. I installed the plugin, used the standard form that came in the box. The form is on the site. When trying to send a message, an error pops up "An error occurred while sending the message. Please try again later."

Answer 1

Install a local mailer like postfix if not needed yet