NAV 2016, O365 Mail error

MaW

Hi,

We get an error trying to use O365 smtp setup in NAV 2016 CU 0.
Entering the mail information in the SMTP setup window and then testing setup gives following error:
A call to Microsoft.Dynamics.Nav.SMTP.MailHelpers.TryGetEmailAddressFromActiveDirectory failed with the following error: An object of type 'System.DirectoryServices.AccountManagement.GroupPrincipal' cannot convert to type 'System.DirectoryServices.AccountManagement.UserPrincipal'.

All clients get this error. However the server does not get error.
It have worked on old clients, but now clients are updated to Windows 10, and the error is there.

Any thoughts?

Thanks,

//Mads

MaW

Correction, it worked with an on premise Exchange server. And stopped after changing to O365.
Server is running in Azure and Clients auth. using O365 credentials.