I can't get "Start URL to display in main frame" working

CMK version: Distributed monitoring, master node on 2.0.0p15.cre.
OS version: Oracle Linux Server release 8.4

Error message: none

I set up some dashboards for our teams (owner cmkadmin) and I want to configure users syncronized from our AD with a different start url based on some groups membership.
I configured LDAP connection to our AD DCs, defined group as needed and chose to creare users immediatly. It seems to work fine, I got users roles correctly assigned based on groups membership.
I tried to update that connection to add also “Groups to custom user attributes” to set the start url, using the same CN previuosly used to define roles.

I can’t get it working, when users login they get always the main dashboard. I tried also to delete and resync users but with no changes.

What I’m doing wrong?

CMK version: Distributed monitoring, all nodes update to 2.0.0p20.cre

Still nothing changes.
Any suggestion?