Rich Snippet for thumbs up/thumbs down

Hi,

I’ve configured WP-Postratings so a user can give a Thumbs-Up(+1) or Thumbs-Down (-1).

The Rich Snippet is displayed like this:

<meta itemprop="url" content="https://www.scribbr.nl/scriptie/voorwoord-van-de-thesis/"><div style="display: none;" itemprop="aggregateRating" itemscope itemtype="https://schema.org/AggregateRating">
<meta itemprop="bestRating" content="2">
<meta itemprop="ratingValue" content="1">
<meta itemprop="ratingCount" content="1">
<meta itemprop="reviewCount" content="1">

As you can see bestRating is somehow set to 2 instead of 1. This results in incorrect the RichSnippets.

How should I config WP-Postratings Thumbs-up/Thumbs-down for the Rich Snippets to display the correct results?

Thanks ??

https://www.ads-software.com/extend/plugins/wp-postratings/