@fkrauthan yeah disabling the preview gives the same unhelpful message. I did manage to decompile the the java behind the code and if I understand correctly its trying to ask security questions.

catch (SecurityQuestionRequiredException sqre)
      {
        count++;
        if (count >= 5) {
          throw new Exception(Messages.msg_unexpected_error);
        }
        String answer = this.securityTokenManager.getSecurityQuestionAnswer(sqre.getQuestion());
        if (!StringUtils.isEmpty(answer))
        {
          previousCookies = sendSecurityQuestionAnswerAndGetNewSecurityToken(sqre.getUrl(), answer, previousCookies);
          if (previousCookies != null)
          {
            this.securityTokenManager.saveSecurityToken(previousCookies);
            retry = true;
          }
        }
        else
        {
          throw new Exception(Messages.lbl_cancelled_security_questions);
        }
      }