i just took over a site for a client who is using Mailgun plugin to send emails from things like contact form notifications. The first thing I did was create an account for myself and received the welcome email to a Gmail address as expected. Next I changed the config of one of the contact forms to notify me at that same address when it has been filled out. It was previously sending to an address in the domain of the website with no problems. When I changed it to my @gmail address, I did not receive it. I also tried changing the default Wordpress address which I did not receive a confirmation email for either. I tried a non-gmail address (different from the domain of the site) which also was never delivered.
I'm checked the headers of the welcome email that I DID receive and it appears to be going through Mailgun as well so I'm not sure what the issue could be. Can anyone recommend some troubleshooting steps?