Solve WordPress Fatal error: Unknown: Cannot use output buffering in output buffering display

solveWordPressfatal error: unknown: cannot be displayed on unknown output buffer at line 0

Recently, when some netizens try to customize the appearance of the website through the WordPress dashboard, the following error message will appear ▼

"Fatal error: Unknown: Cannot use output buffering in output buffering display handlers in Unknown on line 0"

• fatal error: unknown: cannot use output buffering in display handler for unknown output buffering at line 0

And no new ones have been added for a whileWordPress plugin, but don't know what to do?

a lot to learnWordPress websiteNewbies don't know how to debug WordPress error issues...

How to solve Fatal error: Unknown: Cannot use output buffering in output buffering display?

WordPress Fatal ErrorHow to deal with it?

After the WordPress website is moved, the front page of the front page is blank and the background is also blank, what should I do??

It is recommended to enable "WordPress debug mode" to troubleshoot WordPress.

How to enable WordPress debug mode?

1. Edit the "wp-config.php" file in the root directory of your WordPress site;
2. will"define('WP_DEBUG', false); ",change into"define('WP_DEBUG', true); "
3. After enabling WordPress debugging, refresh the error page, and the path and error message of the plugin or theme that caused the error will be displayed;

/**
* 开发者专用：WordPress调试模式
*
* 将这个值改为true，WordPress将显示所有用于开发的提示
* 强烈建议插件开发者在开发环境中启用WP_DEBUG
*
* 要获取其他能用于调试的信息，请访问Codex
*
* @link https://codex.wordpress.org/Debugging_in_WordPress
*/
define('WP_DEBUG', true);
//define('WP_DEBUG', false);

• Finally "define('WP_DEBUG', false); "modified back"define('WP_DEBUG', false); . "

After refreshing the error page, a plugin prompt message similar to the following that caused the WordPress error will be displayed▼

Strict Standards: Redefining already defined constructor for class PluginCentral in /home/eloha/public_html/etufo.org/wp-content/plugins/plugin-central/plugin-central.class.php on line 13

• The preliminary judgment is that it is a WordPress fatal error caused by a WordPress theme or a WordPress plugin, so it is necessary to record which WordPress plugin has an error message, and then eliminate one by one.
• Generally, when troubleshooting a website, you need to disable all plugins and switch to the default theme.
• Understandably, most webmasters are reluctant to do this because it affects site visitors by causing them to browse sites that don't have the original functionality.

Recommended UseHealth Check & Troubleshooting PluginCheck, click the link below to viewspecific method▼

What to do with WordPress errors? Health Check & Troubleshooting plugin troubleshooting

When there are some fatal errors on the WordPress site, and the cause cannot be found, all plugins must be disabled, and then enabled one by one, in order to observe whether it is the WordPress theme or which WordPress plugins are causing the conflict.However, disabling all WordPress plugins will definitely affect…

We found 6 WordPress plugins that can cause WordPress fatal errors:

1. Autoptimize
2. Heroic Favicon
3. Elementor
4. Contact Form 7
5. Askimet Anti-Spam
6. Add to Any

• (The last triggers the "500: Internal Error" message) The fatal error message is thrown.
• These 6 WordPress plugins can cause fatal errors, so you need to test disable them one by one.