| Symptom | Real Cause | Fix | | :--- | :--- | :--- | | "Authentication Failed" | Wrong Pre-Shared Key or X.509 cert | Re-enter PSK or re-import certificate | | "Tunnel disabled" | Firewall blocking UDP ports 500 & 4500 | Open ports or enable NAT-T | | "Failed to initiate IKE" | Gateway IP mismatch | Verify the remote VPN server address | | | This is normal! | No action needed |
In many cases, users looking for an "activation key" are actually looking for a . A PSK is not a license key; it is a credential used to authenticate your connection to a specific VPN gateway (like a Cisco or Zyxel router). shrew soft vpn client activation key