Hi inovacrea,
Thanks for the suggestion. However 5xx error codes mean that the server was unable to fulfill the request and some internal error occurred.
https://en.wikipedia.org/wiki/List_of_HTTP_status_codes#5xx_Server_Error
So it is not possible to dynamically generate these error pages using a plugin. But you can create and save a static page and use it as an error document.
– Go to WP-Admin > Pages > Add New and create separate pages for 500 and 503 errors.
– Open this page, press Ctrl+S, choose “Web Page, HTML only” and save it as 500_error.html
– Upload this file via FTP or file manager and add the following to your .htaccess file:
ErrorDocument 500 /500_error.html