Why can't I change a user's role even though I'm in the Admin role?

I’m Admin, but I can’t edit other users. Could you help me?

I guess you have LDAP role sync = role is comming from LDAP, so you are not allowed to change it in the UI. Of course you may try to disable it (if you are aware of consequences in your setup). Check LDAP doc for your Grafana version, e.g.: