Content Optimization not working

We also have the same problem on the multiple sites with the latest Yoast version.

I can confirm that I also have this problem. In my case, this is a Multisite with WPML enabled. As you can see in this snippet from the Chrome Dev Tools console, both WPML and Yoast are part of the problem in my special case.

wp-seo-post-scraper-920.min.js?ver=9.2:1 TypeError: Cannot read property ‘isSavingMetaBoxes’ of undefined
at t.value (refresh-wpml-meta-box.js?ver=4.9.8:1)
at refresh-wpml-meta-box.js?ver=4.9.8:1
at wp-data-920.min.js?ver=4.9.8:1
at Array.forEach (<anonymous>)
at e (wp-data-920.min.js?ver=4.9.8:1)
at wp-data-920.min.js?ver=4.9.8:1
at a (wp-data-920.min.js?ver=4.9.8:1)
at wp-data-920.min.js?ver=4.9.8:1
at Object.dispatch (wp-data-920.min.js?ver=4.9.8:1)
at wp-seo-post-scraper-920.min.js?ver=9.2:1
(anonymous) @ wp-seo-post-scraper-920.min.js?ver=9.2:1

I already deactivated Autoptimize and WP Super Cache and hard reloaded the backend, but nothing changed.

@jodeleit We are aware of this issue with Yoast SEO and WPML and there is currently an issue report open with our developers here: https://github.com/Yoast/wordpress-seo/issues/11646.

@sahilmoldharia @soldier99 This could be caused by a plugin or theme conflict. Can you try and gather as much information for us as possible? Please perform the following:
1. Make sure the issue doesn’t persist when Yoast SEO is disabled.
2. Check for conflicts.
3. Check for JavaScript errors with your console.
If you find any JavaScript errors related to Yoast SEO or if there is a conflict with a plugin or a theme, you can create a new GitHub issue for our developers. Please report the issue to a third party developer as well.
If you didn’t find any conflicts or errors, we think the issue is specific to your site. We’d need to investigate further but are unable to do so on these forums. You can purchase Yoast SEO Premium and receive our Premium email support and we can help you further.

I have same error as jodeleit and i also have couple more listed here.

TypeError: Cannot read property ‘isSavingMetaBoxes’ of undefined
at t.value (refresh-wpml-meta-box.js?ver=37504eb15c87dddc432f9e4b07df0d96:1)
at refresh-wpml-meta-box.js?ver=37504eb15c87dddc432f9e4b07df0d96:1
at wp-data-921.min.js?ver=37504eb15c87dddc432f9e4b07df0d96:1
at Array.forEach (<anonymous>)
at e (wp-data-921.min.js?ver=37504eb15c87dddc432f9e4b07df0d96:1)
at wp-data-921.min.js?ver=37504eb15c87dddc432f9e4b07df0d96:1
at a (wp-data-921.min.js?ver=37504eb15c87dddc432f9e4b07df0d96:1)
at wp-data-921.min.js?ver=37504eb15c87dddc432f9e4b07df0d96:1
at Object.dispatch (wp-data-921.min.js?ver=37504eb15c87dddc432f9e4b07df0d96:1)
at wp-seo-post-scraper-921.min.js?ver=9.2.1:1

above similar for this script also

wp-seo-post-scraper-921.min.js
components-921.min.js
wp-element-921.min.js
refresh-wpml-meta-box.js

The WPML developers have been informed about this and are currently working on releasing a fix. Their beta version has been tested to be working already so the official version should be released soon. You can view the report here: https://github.com/Yoast/wordpress-seo/issues/11646#issuecomment-440657327

The workaround for the meantime is either to switch to the Gutenberg editor OR to downgrade the plugin to an older version (9.1) which you can download here: https://we.tl/t-zVztzlfHTP.