Oidc logout with post_logout_redirect_uri redirects to KeyCloak url

I’m new to KeyCloak so probably I’m configuring something wrong, but I can’t figure it out. Any help appreciated.

I’m setting up an ASP.NET Core application using KeyCloak OpenIDConnect for authentication. Logging in works fine, but when I log out I’m redirected to the wrong URL. I can see that when logging out this URL is called (I removed the other URL parameters, and had to replace the URLs):
GET https://{my-kc-url}/auth/realms/DeRuwenberg/protocol/openid-connect/logout?post_logout_redirect_uri=https%3A%2F%2F{my-app-url}%2Fsignout-callback-oidc

I would expect to be redirected to https://{my-app-url}/signout-callback-oidc , but instead I’m being redirected to https://{my-kc-url}/signout-callback-oidc
So it looks like it’s replacing the application base URL with the KeyCloak base URL. If I change signout-callback-oidc to e.g. test-callback-oidc I’m being redirected to https://{my-kc-url}/test-callback-oidc

What can be causing this?
Thanks for any help


Solved it myself. It had to do with using IIS as reverse proxy. IIS was rewriting the 302 redirect. See: url rewriting - IIS reverse proxy with rewrites can't handle a redirect from the server we proxy to - Stack Overflow