If you use a third-party theme for your Magento 2 store and have enabled "Use Magefan Blog Comments" as a blog comment option and flushed the Magento cache
but still cannot see the comments on the blog post page on the storefront, please compare layout file blog_post_view.xml in your theme folder
app/design/frontend/ThemeVendor/themename/Magefan_Blog/layout/blog_post_view.xml
and the original blog_post_view.xml layout file from the blog extension code.
app/code/Magefan/Blog/view/frontend/layout/blog_post_view.xml
or
vendor/magefan/module-blog/view/frontend/layout/blog_post_view.xml
you may have missed XML nodes in the theme layout.
Correct theme layout file, save changes and don't forget to flush Magento cache again.