I'm playing around with SharePoint 2013 soap api - particularly the GetGroupsForUser on my company's sharepoint instance.
It seems that it only returns groups when I send a claims string
If I do not send the claims prefix before the domain\username I get an error message like:
<errorstring>User cannot be found</errorstring>. When I do send the
i:0#.w| prefix, no problems at all.
Previously to date, I have never needed that when calling this groups api service. Why is that? Seems like maybe a security setup thing on this company's Sharepoint setup?