If you set SSO_URL to eg. http://sso.pdrobek.apps.devel.xpaas/auth/ you get following error log:

ERROR: Unable to connect to SSO/Keycloak at http://sso.pdrobek.apps.devel.xpaas/auth/ for user mgmtuser and realm xpaas. SSO Clients *not* created
Reason: Check the URL, no response from the URL above, check if it is valid or if the DNS is resolvable.

However if you check the url as log suggest it works fine. Problem is with the slash at the end of url which get duplicated in registration scripts and thus generates invalid url's for registration.