[WP] How to Fix the “There Has Been a Critical Error on Your Website” Error?

My blog can access the front end, but when I try to access the admin panel. My Blog is dead. In this blog you can read an investigation step and solution here.

Investigation

• Enable debug mode by editing the wp-config.php file. set flag below.
  • WP_DEBUG – triggers the debug mode in WordPress.
  • WP_DEBUG_DISPLAY – shows debug messages on the pages’ HTML.
  • WP_DEBUG_LOG – stores error details in the debug.log file.
  • SCRIPT_DEBUG – runs the “dev” versions of core CSS and JavaScript files instead of the minified versions.

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_DISPLAY', true );
define( 'WP_DEBUG_LOG', true );
define( 'SCRIPT_DEBUG', true );

• View the debug message from the browser

OK, I have found the root cause, It is from WordPress Plug-in All in One SEO – Best WordPress SEO Plugin

Solution

disable plug-in by renaming folder wp-content/plugins to incorrect name such as
- old all-in-one-seo-pack
- new _all-in-one-seo-pack

• FTP to your WordPress Host and Navigate to wp-content/plugins
• rename plugin that shows an error in the debug log.

• Refresh WordPress Again.
• WordPress will detect some directories that are missing and automatically disable the plugin. ( All in One SEO)
• My Blog is back !!!! (Can access front and back end)

Recap Step Note

if Enable WordPress debug mode doesn't help or you can’t access the admin panel,

- wp-content/plugins conflict check

Note: if  you have access to the WordPress admin area, disable all pluin first and reactivate plugins one by one

• disable all plugins in wp-content/plugins (rename the plugins folder to plugins.backup )
• Refresh your site. If it loads normally, that indicates a conflicting plugin.
• rename plugins.backup folder to plugins
• try to reactivate plugins one by one, reloading the web page every time.

- wp-content/themes conflict check (Switch to a Default Theme)

Note: if  you have access to the WordPress admin area, try switch the active theme to a WordPress default one such as Twenty Twenty-Four - WordPress theme | WordPress.org

• upload default WordPress theme (Download from: WordPress Themes | WordPress.org)
• disable your active theme such as mytheme2024 in wp-content/themes (rename mytheme2024 folder to mytheme2024.backup)
• Refresh your site. If it loads normally, that indicates a conflicting theme.