If you are getting this error message your PHP site:
HTTP Error 404.11 - Not Found
The request filtering module is configured to deny a request that contains a double escape sequence.
You can add the code below to your web.config file in the root folder, if there is no web.config file, you can create a new one.
<
configuration
>
<
system.webServer
>
<
security
>
<
requestFiltering
allowDoubleEscaping
=
"true"
>
</
requestFiltering
>
</
security
>
</
system.webServer
>
</
configuration
>