This message usually appears when WordPress detects a PHP fatal error during page generation, even if the rest of the site appears to work normally.
Since the issue occurs while browsing the Media Library, I would recommend:
1. Enable WordPress debugging in wp-config.php:
define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);
2. Check /wp-content/debug.log immediately after reproducing the issue.
3. Test with all plugins temporarily disabled and switch to a default theme to rule out a plugin or theme conflict.
4. Review server error logs (PHP/Fatal Error logs) through your hosting control panel.
5. If image optimization, media management, or gallery plugins are installed, test with those disabled first, since the issue occurs while paging through Media Library items.
The screenshot alone does not confirm a WordPress core bug. The debug log or server error log should identify the specific component causing the fatal error.
Please share any errors found in debug.log and we can investigate further.
