There are many factors that impact deliverability that aren't reflected in the type of simple test InboxTrail conducts. Like most ESPs, your reputation builds on Mailgun as you send with us. If for whatever reason you are experiencing a deliverability problem, you can always reach out to us and we'll help you with any issues you have. We support many large and fast growing customers who are all seeing a >99% delivery rate.

Our support team is here to help 24/7. We have a great team here that is proud of the work we do for our customers.

Disclosure: I lead product development at Mailgun.