I've just installed the addon. I found that it doesn't show preview. Could it be that thumbnail generator just need the .episerverlogin cookie? In our case we're using ADFS and I wonder if there is a workaround or configuration change that enable the preview module?
OK. I might find a solution:
By default AB Testing module try to using .EPiServerLogin or .AspNet.ApplicationCookie to authenticate against EPiServer. Changine the cookiename in startup.cs will make it compatible with AB Testing module.
AuthenticationType = WsFederationAuthenticationDefaults.AuthenticationType,
CookieName = ".AspNet.ApplicationCookie"
Thanks for sharing the solution! I think you can mark your own post as answered :)