Website hosted in Plesk is unavailable: Invalid command 'php_flag' or 'php_value'

Symptoms

• A website or Plesk site preview is inaccessible with any of the following errors:

  CONFIG_TEXT: 500 internal server error

  ---

  CONFIG_TEXT: 503 Invalid command 'php_flag', perhaps misspelled or defined by a module not included in the server configuration.

• The following error message is shown on the Home page in Plesk:

  PLESK_ERROR: Unable to generate the web server configuration file on the host example.com because of the following errors:
  Template_Exception: AH00526: Syntax error on line 2 of /var/www/vhosts/system/example.com/conf/vhost.conf:
  Invalid command 'php_flag', perhaps misspelled or defined by a module not included in the server configuration

Cause

Site code contains unsupported directives: PHP directives php_flag and php_value  that are not supported in modern PHP versions. They were supported in PHP as Apache module only (mod_php Apache module) that is now deprecated as it is considered outdated and insecure.

Resolution

1. Login to Plesk

2. Go to Domains > example.com > File Manager and open .htaccess file for editing.

   Note: .htaccess file may be located in domain subdirectories.

3. Comment out php_flag and php_value lines (put sign # at the beginning of the line) or remove completely:

   

4. Click OK to apply the changes.

5. Open Domain > example.com > PHP Settings and add directives from step #3 in predefined parameters (like, post_max_size) or in the Additional configuration directives field. Example of an additional directives:

   CONFIG_TEXT: display_startup_error on
   max_input_vars = 2000
   html_errors on
   allow_call_time_pass_reference 1
   magic_quotes_gpc on

   
   

   Note: For PHP directives use php.ini syntax. Do not use php_flag and php_value prefix.