Simply.com uses an advanced filtering system (Web Application Firewall) to prevent and block attacks, abuse, and exploitation of vulnerabilities on our customers' websites.
If this filter detects what it considers an attempt to misuse your website, it will display a 555 error and terminate the connection for that specific visitor. This may include too many failed login attempts, disallowed HTTP requests, or visits from IP addresses known for attacks and spam.
You can view the specific reason for the block by reviewing the logs for your product. This is done under "Webserver logs" -> "Webserver Application Firewall" in our Control Panel.
This error code used to be HTTP 406, but that is no longer the case.
Well-known third-party services such as Googlebot, Bing, Jetpack, PayPal, Facebook, ManageWP, etc., are whitelisted in our security filter.
In general, we do not recommend whitelisting security services, as our security filter is itself a security component — removing it to scan security doesn’t make much sense.
If you wish to scan our servers or a site hosted on them, you are free to do so — but we kindly ask that you notify us in advance as a matter of good practice.
Article from the support category: PHP
