Please post a copy of your /etc/sssd/sssd.conf (anonymised of course). Most likely you just need to move the ssh_users group to sssd.conf, you can use the realm stuff below, but I recommend editing the sssd.conf itself. Ensure that "access_provider" is set to simple and add/edit the line "simple_allow_group". To activate this feature, use 'access_provider = krb5' in your SSSD configuration. In the case where the UPN is not available in the identity backend, sssd will construct a UPN using the format [email protected]_realm. CONFIGURATION OPTIONS. If the auth-module krb5 is used in an SSSD domain, the following options must be used.