Yoast SEO not working anymore

Hello,

In blog messages, my Yoast SEO Snippet box is not working anymore. It is empty so I can’t even see the Site title, meta description and the Yoast suggestions etcetera. It worked fine yesterday, and now it’s not.

I have updated my site to WordPress 5.0 and I am still using the classic editor. All my plugins are updated to the latest version and the Yoast plugin is at version 9.2.1.

All my settings are right, like:

Can you confirm you have the right user permissions? You can check by going to Users->Your Name->Yoast SEO settings (may need to scroll down) and confirm that both “disable SEO” and “disable readability” are unclicked?
Can you confirm that the Keyword, Readability, and MetaBox insights are all enabled by going to SEO->Dashboard->Features and checking that Readability, Keyword, MetaBox Insights are both enabled?
Can you confirm that the SEO and Readability are enabled on the posts? You can check by going to SEO->Titles and Metas->Post Type and seeing that the Yoast SEO Meta box says “show”?