Enterprise Gateway unable to retrieve SSAS tabular data on SQL Server 2016 CTP

Folks, we were able to resolve our issue.  It was with the login to local AD account resolution.   Here is some text I received from our Network admin.  Your scenario may be completely different but this might be something to check.

The issue was because our local domain UPN did not match our Office365 Tenent UPN (xxxxx.com).    We cannot easily change our local domain name, and we cannot sync our local domain name out to Office365 because it is not an externally routable domain.  For it to be externally routable, it would have to end in something like “.com”, “.net”, etc.   Others may run into this because it is a common practice is to name ones local domain name as something that is not externally routable, such as “companyXYZ.local”.

A workaround to this problem is to add the external domain as an alternate UPN suffix on the domain.  You can do this in the Active Directory Domains and Trusts properties.  Just type the domain suffix in the UP suffixes field, and click the Add button.   After this is done, for each user that you want to be able to authenticate with the alternate UPN, you need to change their AD account properties and change the logon name UPN suffix from whatever the default was to your new suffix.  These suffix changes in AD can be scripted via PowerShell for large changes or many users.  The downside to this suffix change is if you have any applications or services that are using the old suffix for authentication, the application or services will need to be updated, or if they can’t be updated, they will be unavailable to those associates setup to authenticate with the new UPN.