WE cannot see your wp-admin page(s). Please tell us what the issues are.
Regarding buttonizer, I recommend asking at https://wordpress.org/support/plugin/buttonizer-multifunctional-button/#new-post so the plugin’s developers and support community can help you with this.
I already install health check plugin and get the result as the following:
3 Recommended improvements
1. Have a defaul theme available
Themes add your site’s look and feel. It’s important to keep them up to date, to stay consistent with your brand and keep your site secure.
Your site has 1 installed theme, and it is up to date.
Your site does not have any default theme. Default themes are used by WordPress automatically if anything is wrong with your normal theme.
(When I adding a new theme, it appear the notice that: An unexpected error occurred. Something may be wrong with WordPress.org or this server’s configuration. If you continue to have problems, please try the support forums).
2. Outdate SQL server
The SQL server is a required piece of software for the database WordPress uses to store all your site’s content and settings.
For optimal performance and security reasons, we recommend running MariaDB version 10.0 or higher. Contact your web hosting company to correct this.
3.The REST API did not behave correctly
The REST API is one way WordPress, and other applications, communicate with the server. One example is the block editor screen, which relies on this to display, and save, your posts and pages.
The REST API did not process the context query parameter correctly.
1. Install the twentynineteen theme as a fallback in case you ever have to disable your theme.
2. Contact your host about this. HOWEVER, in my experience, this message is a false positive due to weird ways that the PHP/MySQL libraries report things. So, it’s fine to ignore it if your host says they’re using a current version of MySQL or MariaDB.
3. Try the troubleshooting feature of the plugin to see if you can track down what might be causing this.
Thank a lot for your help!
Best wishes,
