title: PHP Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'remove_wpcf7' not found or invalid function name
body: <p>Apologies for this broad question but I am not hugely familiar with the Error Log entries at present.  Any directives on where to begin the relevant research, would be greatly appreciated.</p>
  
  <p>For the past 12 months, I have had the Google Authenticate Plugin, installed on a WordPress powered eCommerce website I work on.  There had been no issues with the Plugin until a recent VPS and WordPress update.  Since said updates, the Google Authenticate Plugin does not recognise any of the inputted codes.  I am not sure if the error is being triggered by the WordPress update or the VPS itself.</p>
  
  <p>I then checked the <code>error_log</code> and saw the below entry when trying to use the Google Authenticate Plugin:</p>
  
  <pre><code>mod_fcgid: stderr: PHP Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'remove_wpcf7' not found or invalid function name in /var/www/vhosts/example.com/httpdocs/wp-includes/class-wp-hook.php on line 286, referer: https://www.example.com/wp-admin/plugins.php
  </code></pre>
  
  <p><strong>Troubleshooting</strong></p>
  
  <p>As standard, I deactivated all Plugins (Except for the WooCommerce Plugin) as well as the WordPress Theme I had created.  I then simply activated WordPress' <a href="https://en-gb.wordpress.org/themes/twentyseventeen/" rel="nofollow noreferrer">Twenty Seventeen</a> Theme.  The error still persisted; leaving me wondering just what is causing the issue.</p>
  
  <p>I can see there is a reference to WordPress' core files.  Maybe there is some incompatibilities?</p>
  
  <p>Any directives on this, would be greatly appreciated ... Even if to just help me expand on this question.</p>