IKEv2/IPsec on Windows: Common Errors & Simple Fixes

- Incorrect credentials or certificate issues.

- Invalid pre-shared key (PSK).

- Double-check username and password.

- If using certificates, ensure they’re installed correctly and match the server.

- Make sure the PSK is correct on both client and server.

- If it still fails, contact ChitaVPN support.

- The VPN client cannot connect due to network or server-side issues.

- Possible mismatch in encryption settings or blocked ports.

- Confirm the server address is correct and reachable (ping the IP if possible).

- Verify the VPN server is online and set to accept IKEv2.

- Check your internet connection; try another network if needed.

- Ensure UDP ports 500 and 4500 are open and not blocked.

- If unresolved, ChitaVPN support can help.

- NAT-T or UDP 4500 might be blocked.

- A firewall or NAT device is dropping IKE packets.

- Open or forward UDP 500 and 4500.

- Enable NAT Traversal (NAT-T) on both client and server.

- If the server doesn’t support NAT-T, either disable it client-side or use another protocol.

- For further help, contact ChitaVPN support.

- Certificate issues: invalid usage, missing, expired, or untrusted.

- The certificate chain is broken or not recognized by Windows.

- Ensure you have the correct (client/server) certificate installed.

- Verify the certificate is valid and not expired.

- Check the certificate chain in Windows’ local machine store.

- If you need assistance, ChitaVPN support can guide you.

- The VPN client can’t reach the server (network/config/firewall problem).

- UDP ports 500/4500 may be blocked.

- Verify the VPN server address is correct.

- Ping the server to test reachability.

- Temporarily disable or adjust the firewall to allow UDP 500/4500.

- Make sure NAT Traversal is enabled if behind a NAT router.

- Confirm the server is configured for IKEv2 with correct encryption settings.

- If you still can’t connect, contact ChitaVPN support.