Sendy (sendy.co) is not sending emails on Windows, but is able to send through SES console

Question

I'm not able to send emails through Sendy which is installed on Windows Server.

Things I have already tried:

1. Switched off windows firewall.

2. Allowed all TCP and UDP requests to Amazon EC2 in security group.

3. Cross checked task schedulers. There are 3 task schedulers running on my EC2 machine.

   1. autoresponders.php
   2. import-csv.php
   3. scheduled.php

Do we require anything else apart from this?

I cross checked my database which has 17 tables and no procs, function or views. I have verified domain solitaireXXXcom and verified email address as [e-mail]. (I hope this is allowed.)

I'm able to send test mails using Amazon SES console, but not through Sendy.