Does the module have any documentation? The normal process for enabling SSO is to add the SSO endpoint to the Discourse
sso url site setting, add an SSO secret key to the
sso secret site setting, then enable the
enable sso site setting. When first setting this up, you’ll probably also want to enable the
verbose sso logging site setting. With that setting enabled, you’ll get details about SSO errors in your site’s error logs (found at Admin / Logs / Error Logs.)
When you have the Discourse settings enabled, you’ll need to be sure that your Discourse site’s URL and
sso secret are added to the SSO provider site.
From the error you are getting, it seems likely that the
enable sso site setting has not been enabled on your Discourse site.
If you run into problems accessing your Discourse site after having enabled SSO, as an admin you can bypass SSO login by going to
/u/admin-login on your Discourse site. Enter your admin email address into the form on the page. A onetime login link will be sent to you.