Update oidc-provider.md

Refer to Mendix Support ticket #247694 for the issue that led to this discovery.

Author: kkunzer

content/en/docs/appstore/use-content/platform-supported-content/services/oidc-provider.md

@@ -576,6 +576,10 @@ In versions of the OIDC Provider above 2.0.0, the sub value was changed from an
 The OIDC Provider service sets a cookie as a means to persist the session in the user’s browser. If the cookie is not properly set, this may lead to problems. For example, when the OIDC Provider service is used to build an IAM Broker, no session is established and the broker may initiate a new session at the upstream IdP, which results in an ‘infinite loop’ of redirects via the user’s browser.
 To ensure the cookie is properly set, the runtime setting com.mendix.core.SameSiteCookies must have value None. See [Environment Details](/developerportal/deploy/environments-details/#samesite) for more information how to set the correct value for SameSite runtime setting. Note that the default value for this setting changed in [Mendix 8.11](/releasenotes/studio-pro/8.11/).
 
+### On-premise Deployment and IIS
+
+When implementing the OIDC Provider service in an on-premise deployment scenario and allowing users to navigate freely between applications, there is an additional setting in IIS that must be configured that is not normally changed for a regular on-premise deployment. Without making this update, when users are already logged in (have the cookie) and they navigate to one of the applications that would need to authenticate with the Provider service, a redirect for authentication will fail because IIS will rewrite the host in the response header resulting in request attempting to authenticate on itself for authentication instead of the Provider service. This is because of a default setting on the Application Request Routing proxy server that is set up in IIS for on-premise deployments. You must disable the "Reverse rewrite host in response header" checkbox under IIS > Server > Application Request Routing > Proxy Settings to prevent this from happening.
+
 ## Authorization{#authorization}
 
 When you are building Mendix apps you need to make two architectural decisions in the area of end-user access: