Hi dodgeuk19,
If you’re able to receive emails from your WordPress site to an email address but don’t receive an email from the plugin, I’d guess that you’re running across one of a few issues:
1. Due to the content of the emails, these providers suspect they are spam and are tossing them.
2. The email headers are getting flagged due to mismatches with the SPF records on your host’s email server or other potential red flags.
There isn’t a lot I can do other than recommend you work closely with your hosting provider to determine the source of the problem. Usually, if a provider blocks email, they’ll provide a return message indicating why. Your host should be able to inspect this for clues. You’ll also probably want to ask them to look closely at the headers of the emails that the plugin is sending out and confirm that they are not falling foul of any of their server’s configurations, or interacting poorly with their SPF records.
Once you have identified the source of the problem with your host, I can show you how to alter the mail headers for emails the plugin sends out to improve your delivery rates. But only your hosting provider can really tell you what needs to change. I can’t guess a solution.
If you’re unable to get anywhere with your host, your other alternative is to use a reputable third-party mailer, like Mandrill. They have an easy-to-use WordPress plugin, wpMandrill, but there are costs associated with them.
