You can share the printscreens here 🤠 Printscreen translated from italian (in bold, the only error I’ve found): ----------- Starting utility 'klnagchk' ... Checking command line options ... OK Basic library initialization ... OK The current device is 'PCCLIENT.DOMAIN.local' Network Agent version is '12 .2.0.4376 (12_2) ' Reading settings ... OK Check your settings ... OK Network Agent Settings: Administration Server address: '192.168.1.11' Use SSL: 1 Compress Traffic: 1 Number of Administration Server SSL ports: '13000' Number of Administration Server ports: '14000' Use proxy server: 0 Administration Server certificate: available UDP port open: 1 Number of UDP ports: '15000' Synchronization interval (min.): 15 Connection timeout (in seconds): 30 Send / Receive Timeout (in seconds): 180 Device ID: 3592288b-61a1-46a9-86c3-d355e6c8adec Attempting to connect to the Administration Server ... Transport layer error connecting to http://192.168.1.11:13000: SSL authentication failed, certificate invalid or out of date. Attempt to send an ICMP packet to the Administration Server Sending ICMP packet 192.168.1.11 [192.168.1.11] ... OK Sent = 1, Received = 1 Attempting to connect to Network Agent ... OK Network Agent is running. Receiving Network Agent Statistics ... OK Network Agent Statistics: Total number of synchronization requests: 0 Number of completed sync requests: 0 Total number of synchronizations: 0 Number of synchronizations performed: 0 Date / time of the last sync request: 11/26/2020 10:31:27 GMT (11/26/2020 11:31:27) Basic library deinitialization ... OK ----------- From client, if I try to open both http or https sites (with both 13000 or 14000 port) it asks for a certificate. It never happened before and, in the same company, I have other 3 clients working perfectly and 3 clients with this problem. All clients have the same Windows version