After mitigating the HTTP Security Header Not Detected Vulnerability in IIS by adding HTTP Response Headers, the Citrix Storefront url may become inaccessible. Users might be presented with the "500 Internal server error" message

When adding the HTTP Response Headers at the Default Website level, the settings are inherited by the Storefront Web application as well. For resolving the HTTP Header Not Detected vulnerability, administrators would be adding X-Content-Type-Options header with the value of nosniff.  This header then gets inherited to Store Web. This causes a problem with Store web as it already has another X- header (X-Citrix-Application) and IIS does not allow two headers.

1. Remove the inherited value from the Store web level 
   • This should resolve the issue. 

Here are the steps to remove the inherited value from the Store web level:

1. Access the Storefront Web application.
2. Locate the configuration file for the Storefront Web application, which is typically named "web.config".
3. Open the "web.config" file in a text editor.
4. Search for the X-Content-Type-Options header entry.
5. Remove the X-Content-Type-Options header entry from the configuration file.
6. Save the changes to the configuration file.
7. Restart the Storefront Web application to apply the changes.

By removing the inherited value of the X-Content-Type-Options header from the Store web level, you will resolve the problem of having two X- headers in the Store Web application .