If there are no Related Posts appearing under some of your posts, it’s most likely because your site wasn’t fully indexed yet. If you’ve only enabled the feature very recently, it might be worth waiting a bit longer for the indexation to complete.
If you’ve enabled Related Posts a while ago, could you try to install and activate this small plugin, by going to Plugins > Add New > Upload in your dashboard:
https://i.wpne.ws/Vdoc
Once you’ve activated the plugin, try to relaunch the indexation (you’ll find the reindex button by clicking on the “Debug” link at the bottom of the Jetpack menu in your dashboard).
If the Related Posts start appearing, you can deactivate and delete this small plugin.
i would like to show at least 4 related products below my listing (filter by category)
To customize the number of posts displayed in the Related Posts area, as well as the category they’re pulled from, you can follow the instructions here:
https://jetpack.com/support/related-posts/customize-related-posts/
I hope this helps.
