title: Forbidden: You don't have permission to access /script.php on this server. (but only sometimes)
body: <p>I have a web application that my clients deploy on IIS servers. One particular client has an issue where they get a <code>Forbidden:  You don't have permission to access /script.php on this server.</code> error. When they try to access <code>script.php</code></p>
  
  <p>The trouble is that <code>script.php</code> is called many times in my application and it is only in one part of my application (a form submit) that i get the above error . In all other instances it works. </p>
  
  <p>Any ideas why this this error would appear? what is it i need to check?</p>