If you are an administrator seeing this error flood in from remote users, check your server logs firstāyou likely have a licensing shortage or a crashed VPN service.
Consult the official GFI Kerio Knowledge Base article (ID: KBA-28201) or post your specific network configuration (ISP, router model, and client OS) on the Kerio Community Forums. Last updated: 2025. Compatible with Kerio Control 9.x and 10.x. error 28201 kerio vpn client
Unlike authentication errors (wrong username/password) or certificate errors (mismatched keys), Error 28201 indicates a between your computer and the Kerio Control server. If you are an administrator seeing this error