iOS MDM server install fails

[SIIL-IT1]

We are looking to deploy mobile protection and I've just tried to install the iOS MDM server on our system in our DMZ that is acting as the external connection/distribution point gateway for our users who travel. The install fails with the following error.... Remote installation has been completed with an error on this device: Fatal error during installation. (The port that you have specified for external connection to iOS MDM service is already in use. Please select another port.) The distribution point is set as a connection gateway with the following details address: %external dns% Establish connection to gateway from Admin Server: Yes Open local port for KSC 11 Web Console - Port: 13299 Open port for mobile devices (SSL auth of the admin server only) - Port: 13292 Open port for mobile devices (two way SSL auth) - Port: 13293 DNS domain names: %external dns%, %internal dns of admin server% Within MDM, additional ports are set as SSL for activation proxy: 17000 Mobile device sync: 13292 Mobile device activation: 17100 What port setting do I need to tweak to get the install to work???