Hi there is an error in your documentation which describes how to add a subdomain for Mailgun.

For the TXT, MX, and CNAME records, your instructions say to use a full host name of mysubdomain.mydomain.com and support.mysubdomain.mydomain.com, BUT what you're really supposed to enter is JUST
mydomian and JUST email.mydomain. If the instructions are followed the way you have it documented, IT DOES NOT WORK! At least for Godaddy!

Now that I've figured this out on my own, it works great and I'm very satisfied with the service. I hope you can correct the documentation. This personally cost me a few hours of research and exerimentation that could have been avoided if the documentation were corrected.

Thanks,
A happy customer,
R. Cunningham