Auto-detection feature for affected IP-addresses
A problem with sending email with Mailgun is: many Mailgun users are using the same IP-address. When another user is sending spam, all emails from that IP-address to Hotmail/Live addresses are blocked, until Mailgun has assegned a new IP-address after a couple of hours (when I create a ticket).
My idea: an automatic affected IP-address detection. When Microsoft returns an error "bad IP reputation", then automatically assign a new IP address and resend the failed emails.