sort by vote with GD STAR RATING plugin

Does anyone have any suggestions as to how I can get the sort by vote count to work with the GD STAR RATING plugin? I have added sorting parameters to a category list on my site but it still isn’t ordering the posts by the number of thumbs up votes.

Here is the link to the category with the GD STAR sorting parameters appended. As you can see, some items which have votes are not showing up at either the top or the bottom.

https://uhurusoftware.com/category/contest/?gdsr_sort=votes&gdsr_order=asc

Does anyone have suggestions of what I should check? Are there options I need to set in the GD STAR RATING admin panel?