There are several possible reasons why you may receive the error 500 - Internal Server Error on your website:

• Incorrect permissions: The permissions for files and folders are not configured correctly
• PHP timeout: A PHP script is trying to access external content and a timeout has occurred
• .htaccess: The structure of the .htaccess file could be incorrect
• PHP memory limit: A process requires more memory than is available and therefore cannot be executed correctly.
• Faulty plug-in / theme: Third-party plug-ins or themes in particular can affect the entire site in WordPress and other content management systems

As a website operator, how can I resolve the issue?

• check error.log: First of all, you should check the log file of your website for current entries. This can often reveal a problem with incorrect authorizations, a PHP timeout or a faulty plugin. You can find the log file here:
  
  • Login to cPanel
  • Under Files, select File Manager
    
    
    
• Check permissions: If there is no error.log file in the logs folder or if the file does not provide any information about error, you should check the permissions of the file or folder you are calling up.
  • To do this, open the public_html folder in the file manager. In the last column Permissions, you can see the permissions for folders and files. The correct permission for files is 0644, for folders 0755. Check the permissions of all files and folders within public_html
    
    
    

  • If the permissions for a file or folder differ, right-click on the file in question and select Change Permissions.
    
    

  • Correct the permissions in the following dialog box.