I have a Sitecore/ADFS integration working with SC 9.3 and ADFS 2019 (on premise). Sign in is working fine. However we can't get the post logout redirect to work. Currently when a user signs out of Sitecore they are taken to an ADFS page that says "You have successfully signed out". We would like the user to be taken back to the Sitecore sign in screen.
I have followed the example found here (https://blog.istern.dk/2019/05/15/sitecore-9-1-identityserver-on-premise-ad-via-adfs/) to create a custom Identity Server plugin. However I cannot figure out how to specify the URL that the user should be directed to after logout is complete. Is that specified somewhere in my custom plugin code? Somewhere in the Identity Server config? Somewhere in ADFS?
The current ADFS configuration information looks like this:
We also noticed an error in the ADFS logs that says this:
I am not really sure I even understand how I am supposed to specify a post logout URL. Does anyone know how I should do that?