Are you or others receiving a 406 error when visiting your site?
Most likely it is caused by mod_security, which acts as a firewall to protect web application attacks.
The solution maybe as-easy-as adding the following to your .htaccess file in-order to disable mod_security:
SecFilterEngine Off SecFilterScanPOST Off
Give it a shot. If this doesn't help, please create a support ticket and one of our technicians will investigate your issue.