"HTTP 500 Internal Server Error" is a common WordPress Error which can make a WordPress panic but be assured that after reading the text below you can easily fix this error and you will never need to Panic. This Internal Server Error in WordPress is commonly occurs due to any Plugin and / or Theme Functions, Corrupted ".htaccess" File and PHP Memory Limit. The details about fixing this error are given in the following text.
1. Check the Corrupt .htaccess File : It is the first step which you should take while troubleshooting the Internal Server Error in WordPress. You can check for the corrupted .htaccess file by renaming the .htaccess file with any other name i.e. .htaccess_old. You can rename the .htaccess file by logging into your site via the FTP, then find the .htaccess file (from the directory where folders such as wp-content, wp-admin, wp-includes are present) and rename it. If this fixes the error then ok, otherwise you should perform the tasks given in the following sections.
2. Increasing the PHP Memory Limit : You can easily increase the PHP memory limit by editing the wp-config.php file. You can edit this file by opening the root directory, then find the editing the wp-config.php file, then download the file and add the following code "define('WP_MEMORY_LIMIT', '64M');" in it. After adding the code, save the file and replace the old wp-config.php file with the new saved one. If the error gets fixed then ok otherwise remove the code from your wp-config.php file and perform for the steps given below.
3. Deactivate All Plugins : If you have done the two solutions detailed above and still the error not gets fixed then it is possible that a Plugin (or Combination of Plugins) is causing this error. To fix this error you should deactivate all the WordPress Plugins. Once you have disabled the plugins and the error gets fixed then you can easily re-install the plugins one by one except the plugin which is causing the error.
4. Re-uploading Core Files : The last option which you can try at your end is "Re-uploading of Core Files (wp-admin and wp-includes folder)" from a fresh WordPress install.
5. Contact Your Hosting Provider : If none of the solutions (detailed above) works then you should contact your hosting provider about the error and wait for them to fix this error for you.
[RESOLVED] Error: "500 Internal Server Error" in Wordpress
500 Internal Server Error in Wordpress.