RT-AC68U-E308

Cause

NAT-T keepalive timeout on UDP port 4500

Fix Steps

1. Verify VPN server address and port configuration
2. Check VPN credentials are current and not expired
3. Ensure correct VPN protocol is selected (IKEv2/IPSec recommended)
4. Verify firewall rules allow VPN traffic on required ports
5. Try switching between UDP and TCP protocols
6. Update VPN client to latest version
7. Contact VPN provider support with error logs if issue persists

Related Errors

• E9986 – Linksys E9986 VPN Tunnel Error
• NVG2846 – Arris NVG2846 VPN Tunnel Error
• TL-AX8244-E81 – TP-Link TL-AX8244-E81 VPN Tunnel Error
• SVG5555 – Arris SVG5555 VPN Tunnel Error