The server returned a generic 500 response because the request could not be processed. This usually happens when PHP encounters a fatal error, when the .htaccess file contains invalid directives, or when memory limits are exceeded. The error stops WordPress from loading any page.
Underlying issues often involve mismatched PHP versions, corrupted core files, or incorrect file permissions. When the server cannot execute the script, it returns the 500 status without revealing details to the browser.