Widget isn’t showing at all
Six causes, in the order they are worth checking. Most cases are the first three.
Live site looks different from the editor
If the live site looks different from the editor, the changes were not published.
The short answer
If the live site looks different from the editor, the changes were not published. Click Publish in the widget editor.
If Publish is greyed out, there is nothing left to publish and your website’s own cache is serving an old copy.
Publishing
Edits in the widget editor do not go live until published. The button greys out when everything is published, which makes it a reliable test: if it is still active, that is your answer.
Website caching
With everything published and the live site still wrong, your site or CDN is serving a cached page. Purge the cache, or wait — most hosts refresh within an hour. WordPress caching plugins and Cloudflare are the usual suspects.
New reviews in the editor but not on the site
Same two causes in the same order. Publish first, then cache.
Questions
Other common problems
New reviews haven’t appeared yet
New reviews appear in the widget on their own, but not instantly.
Layout is broken, cut off or overlapping
Layout problems come from your site’s CSS interacting with the widget.
Adding a review source
Most sources connect by pasting a link to your public profile on that platform.