I faced this issue “Failed to create a session; confirm that the user has the proper privileges to log on to Microsoft Dynamics” when I imported MS contoso data into my new created AX environment. Though this is not specific to MS contoso data import, you can have on original post which solved my problem too.
http://www.ksaelen.be/wordpresses/dynamicsaxblog/2013/02/ax2012-r2-db-sync-failed-to-create-a-session/
http://www.ksaelen.be/wordpresses/dynamicsaxblog/2013/02/ax2012-r2-db-sync-failed-to-create-a-session/
