Hello @danielbenjamins
We are sorry about the critical error. Often, we see problems occur in combination with another plugin or theme. The fastest way to rule out any conflict, is to deactivate all non-Yoast plugins and switch to a standard theme like Twenty Twenty.
Please test this on your development or staging site, if you have one. If not, we recommend using the Health Check & Troubleshooting plugin. This plugin has a troubleshooting mode, which does not affect normal visitors to your site.
If you’re unfamiliar with checking for conflicts, we’d like to point you to a step-by-step guide that will walk you through the process: How to check for plugin conflicts
If you do not feel comfortable to do this yourself or if this does not solve your issue, our Yoast SEO Premium plugin comes with one year of (technical) support.
@gekondo The fatal error “failed to open stream: No such file or directory in” occurs when the plugin installation or update couldn’t be completed correctly. The fatal error is telling you that the plugin couldn’t find one of the core Yoast SEO plugin files. Therefore, we recommend that you manually install the plugin via FTP (on your staging site first).
