After migration from keycloak 3.2.1 to 3.4.1 we can no longer manage groups in one of our realms. When clicking at 'Groups' in the administration console I get a 'Resource not found...' page.
It seems to be caused by invalid REST requests to load the groups. The requests are send to urls with the realms id instead of its name:
I replaced in 'themes/base/admin/resources/js/controllers/groups.js' both occurrences of 'realm.id' with 'realm.realm'. That seems to fix the problem.