Solved
Adobo_SupportusAccepted solution
Level 7
October 16, 2015
There are a couple of common issues that can prevent you from successfully inviting a new user to DTM, read about how to troubleshoot them here: https://helpx.adobe.com/dtm/kb/troubleshooting---why-am-i-unable-to-invite-users-to-dtm-.html