Follow our verified network engineer checklist to diagnose and resolve stuck connections, TAP driver crashes, infinite reconnect loops, and firewall blocks across Windows, Mac, iOS, and Android.
If your VPN is stuck on "Connecting..." forever, your local Wi-Fi router or ISP is blocking the default UDP port used by WireGuard. Go to Settings > Protocol > OpenVPN TCP. Because Port 443 is the standard SSL port for all web traffic, network firewalls cannot block it without shutting down the entire web.
The #1 reason VPNs fail to connect is strict network firewalls blocking UDP ports. Switch your VPN protocol from WireGuard (UDP) to OpenVPN TCP (Port 443). Because HTTPS traffic runs over Port 443, routers and firewalls cannot block it without disabling the entire internet.
Stale DNS cache records frequently cause domain resolution failure when switching between regular Wi-Fi and VPN tunnels. Open Command Prompt as Administrator and run: "ipconfig /flushdns", followed by "netsh winsock reset".
If you have previously installed multiple VPN clients (e.g. NordVPN, ExpressVPN, Surfshark, or OpenVPN GUI), their virtual network drivers conflict. Open Device Manager > Network Adapters > uninstall duplicate TAP-Windows adapters and reinstall your primary client.
Commercial VPN servers occasionally undergo maintenance or become blacklisted by target websites. Toggle your Kill Switch off and on, then connect to a different neighboring city node (e.g. switch from New York to Chicago).
Third-party antivirus programs (Norton, McAfee, Bitdefender) often flag VPN background daemons as suspicious proxy tools. Add your VPN’s executable (.exe) to your antivirus firewall exclusion list.
If your VPN connects but will not load any web pages, your ISP has high MTU overhead causing packet fragmentation. In your VPN client settings, reduce MTU from automatic (1500) to 1420 or 1380.
Use our interactive VPN Error Code Solver to get instant command-line fixes tailored to your operating system.
Launch VPN Error Code Solver