Open a browser window, in the address bar type the federation server’s DNS host name, and then append /adfs/fs/federationserverservice.asmx to it for the new federation server, for example:
https://fs1.testdomain.local/adfs/fs/federationserverservice.asmx
Press ENTER, and then complete the next procedure on the federation server computer. If you see the message There is a problem with this website’s security certificate,
click Continue to this website.
The expected output is a display of XML with the service description document. If this page appears, IIS on the federation server is operational and serving pages successfully.
Next check the following:
- Log on to the new federation server as an administrator.
- On the Start screen, type Event Viewer, and then press ENTER.
- In the details pane, double-click Applications and Services Logs, double-click AD FS Eventing, and then click Admin.
- In the Event ID column, look for event ID 100. If the federation server is configured properly, you see a new event—in the Application log of Event Viewer—with the event ID 100.
- This event verifies that the federation server was able to successfully communicate with the Federation Service.
Ref: – https://docs.microsoft.com/en-gb/windows-server/identity/ad-fs/deployment/verify-that-a-federation-server-is-operational