Since there are a lot of reasons which may cause server errors, their diagnostics is very complex and tedious.

If a server error occurs, the first thing to do is view the error.log file. This file may contain a line with the error description.

• Typical situation when a server error may occur is exceeding the allowed server permissions.

  For example: the system creates and saves a page with the 0777 permissions, while the maximum permission allowed by the server is 0644. The server will return the 500 error upon attempt to access the page.

  To eliminate this error ensure that the server allows to access files whose CHMOD attributes are 0777.

  For Bitrix Site Manager, add the following lines to the dbconn.php file:

  define("BX_FILE_PERMISSIONS", 0777);
  define("BX_DIR_PERMISSIONS", 0777);

  Instead of 0777, you can use values allowed by the server for files and folders, respectively. The following values are usually sufficient:

  define("BX_FILE_PERMISSIONS", 0644);
  define("BX_DIR_PERMISSIONS", 0755);

• Another prevailing reason is invalid server configuration or using forbidden directives (for example, in .htaccess). In this case, remove or comment the failure line in the file.

• Note! If PHP runs as CGI, the 500 error may be cause by a PHP fatal error. In this case, you are recommended to check the program code and diagnose the error.

• Internal server errors may come about when a CGI script runs on the Apache server and the execution time exceeds the maximum allowed period specified in the server configuration.