Check that you can navigate to your AD FS namespace’s initiated sign-on page.
The URL is in the format
https://
<namespace>
<adfs-server-hostname>
/adfs/ls/idpinitiatedsignon.aspx
,
where
<namespace>
is the namespace for the ADFS server
(either
adfs.
or, if you use the Secure Token Service (STS),
sts.
) and
<adfs-server-hostname>
is the
host name for the ADFS server.