500 Internal Server Error on WordPress

Is this your problem?

• A plain "500 Internal Server Error" or "HTTP ERROR 500" page
• Only wp-admin fails, or only the front of the site
• It appeared after installing a plugin, or after a move

What usually causes it

How to fix it, step by step

1. 1

   Read the server error log first

   This saves the most time. In cPanel it is under Metrics, then Errors, or a file called error_log in the site folder. On other hosts, ask support for the PHP and web server error log around the time of the error.

2. 2

   Reset .htaccess

   Rename .htaccess in the site folder to .htaccess-old. If the site loads, log in, go to Settings, then Permalinks, and press Save to write a fresh one. A clean WordPress .htaccess looks like this.

   Copy

   # BEGIN WordPress
   <IfModule mod_rewrite.c>
   RewriteEngine On
   RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
   RewriteBase /
   RewriteRule ^index\.php$ - [L]
   RewriteCond %{REQUEST_FILENAME} !-f
   RewriteCond %{REQUEST_FILENAME} !-d
   RewriteRule . /index.php [L]
   </IfModule>
   # END WordPress

3. 3

   Switch plugins off from the file manager

   Rename wp-content/plugins to plugins-off. If the site returns, rename it back and turn plugins on one at a time until the error comes back.

4. 4

   Raise the memory limit

   Add this to wp-config.php. If the log still says memory exhausted, ask the host to raise PHP memory_limit.

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   define( "WP_MEMORY_LIMIT", "256M" );

5. 5

   Fix permissions

   Folders should be 755 and files 644. wp-config.php can be 640 or 600. Many file managers can set this, or ask your host to reset them.

Stop it happening again

• Keep a copy of a working .htaccess.
• Install plugins one at a time on a copy of the site first.
• Check the error log once a month, before small warnings become outages.