GoToWebinar: Cannot preview "AttendeeRollup"



I'm working on my GoToWebinar-Silverpop integration, and "AttendeeRollup" seems to be the best entity to query. 



  • Returns webinar session attendees along with any questions asked, poll questions answered, and survey questions answered by that attendee.
  • Each attendee is returned as a unique record with all of their questions and answers rolled up into three fields:
    • All questions and answers.
    • All poll questions and answers.
    • All survey questions and answers.


But this is the only entity which I can't preview. This is the error message I get:


An error has occurred. If the error message is unclear, read this article for help diagnosing the problem.

ERROR: Exception Type : ArgumentNullException Message : Value cannot be null. Parameter name: values


Any ideas what could be wrong here?