How to: Resolve 503 Browser Error
=================================

.. contents::

How the Issue Manifests
-----------------------

- 503 error when accessing the domain in the browser:
  
  .. image:: /images/503-error.png
     :alt: 503 error

- httpd-UDS error in the domain-level error log. This log is located at ``/home/{unixuser}/var/{domain.com}/logs/error.log`` 
  or ``error-ssl.log``, replacing ``{unixuser}`` and ``{domain.com}`` with the corresponding information 

  .. code-block::

     [root@ga-jan27 public_html]# tail -f /home/examplec/var/example.com/logs/error.log
     [Fri Feb 10 14:13:21 2023] [proxy:error] [pid 13801:tid 139821150353152] (2)No such file or directory: AH02454: FCGI: attempt to connect to Unix domain socket /var/run/examplec-remi-safe-php74.sock (examplec-remi-safe-php74-proxy:8000) failed
     [Fri Feb 10 14:13:21 2023] [proxy_fcgi:error] [pid 13801:tid 139821150353152] [client 108.17.85.15:56513] AH01079: failed to make connection to backend: httpd-UDS

Cause of the Issue
------------------

The most common causes of this issue on an InterWorx server are: 
  
- PHP-FPM needs to be restarted
- The PHP-FPM pool file for the domain is missing or corrupted, and needs to be recreated
  
How to Resolve
--------------

There are three ways that are often able to resolve the issue: 

- Restarting PHP-FPM
- Toggling the PHP version in SiteWorx
- Re-writing and resetting PHP-FPM files on the server

To Restart PHP-FPM
^^^^^^^^^^^^^^^^^^

From NodeWorx 
'''''''''''''

#. Log into NodeWorx from the browser (https://ip.ad.dr.ess:2443/nodeworx)
#. Navigate to **System Services > Webserver > Overview**
#. Under Restart PHP-FPM, click **Restart**. This may take a few seconds to complete
 
   .. image:: /images/nw-restart-php-fpm.png
      :alt: php-fpm restart button

From the CLI
''''''''''''

#. Log in to the server at the CLI as root, either via SSH or from the terminal
#. Run either of the following commands--either will restart the service, though the first is 
   recommended. This process may hang for a few seconds before completing:

   .. code-block::

      ~iworx/bin/php-fpm.pex --restart-fpm

   .. code-block::
     
      systemctl restart php-fpm 

To Toggle the Domain PHP Version in SiteWorx
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. note::

   This option requires that Multiple PHP is enabled on the server, and that the SiteWorx account
   has access to more than on PHP version. 

- Follow :doc:`this documentation </siteworx/domains_and_websites/php/change-php-versions>` on how to change the PHP version for a domain in SiteWorx
  
  - Change the PHP version to a different version, save that change, and then change it back to the 
    original PHP version

To Re-Write and Re-Set PHP-FPM files
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

#. Log in to the server at the CLI as root, either via SSH or from the terminal
#. Run each of the following commands, in turn. These processes may hang for a few seconds before completing:

   .. code-block::

      ~iworx/bin/php-fpm.pex --write-files
      ~iworx/bin/php-fpm.pex --reset-files
      ~iworx/bin/php-fpm.pex --restart-fpm 

   - The flags perform the following tasks: 
  
     - **--write-files**: Writes out php-fpm pools, fcgi, etc
     - **--reset-files**: Deletes all InterWorx-owned files and re-creates them
     - **--restart-fpm**: Restarts php-fpm services

Things to Keep in Mind
----------------------

While this documentation describes the most common reason for a 503 error on an InterWorx server, 
it is possible that the error may be caused by something else. If the above steps do not
resolve the issue, please submit a ticket to `https://support.interworx.com <https://support.interworx.com>`__.