Hi Daniele,
in SAP NetWeaver Administrator (nwa) start the Security Troubleshooting Wizard and check if SPNego authentication was successful (SPNegoLoginModule).
If you don't see any SPNego negotiation information, check the Service Principal Name (SPN) configuration of the service user in Microsoft Active Directory system.
The hostname defined in the parameter enrollURL0 (Client Registry: [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\SAP\SecureLogin\profiles\<ProfileName>]) should be defined in the Service Principal Name (SPN) of the service user (HTTP/<Hostname>).
Best regards,
Frane