VPN Keeps Disconnecting
VPN drops randomly, won't connect, or shows authentication errors
⚠ Common symptoms
- VPN connects but drops within seconds or minutes
- "Authentication failed" or "Credential error" messages
- VPN shows connected but company resources aren't accessible
- Works at home but fails on hotel, cafe, or guest Wi-Fi
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1
Confirm your credentials are still valid
Try signing into your company's web portal or work email using the same username and password. If that also fails, your account may be locked or your password expired — contact IT or your HR self-service portal before troubleshooting the VPN client itself.
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2
Switch the VPN tunnel protocol
Some networks (hotels, airports, corporate guest Wi-Fi) actively block VPN protocols like PPTP and L2TP. In your VPN client settings, switch to IKEv2, WireGuard, or SSL/TLS (TCP port 443) — port 443 is almost never blocked since it's the standard HTTPS port.
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3
Temporarily disable antivirus and firewall
Third-party security tools with "network protection" features can intercept and kill VPN tunnels. Disable yours temporarily, attempt to connect, and if it works, add your VPN executable and the VPN's virtual adapter as exceptions in the security software settings.
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4
Fix your system clock — time sync is required for authentication
VPN protocols including IKEv2 and Kerberos require your clock to be within a few minutes of the server's time. On Windows: right-click the clock → Adjust date/time → toggle Set time automatically off, then back on. On Mac: System Settings → General → Date & Time → Set automatically.
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5
Reinstall the VPN client completely
Corrupted TAP/TUN drivers or broken configuration files cause persistent failures. Uninstall the VPN client entirely, restart, then download a fresh installer from your company's IT portal or the vendor's official website. A clean install replaces the virtual network adapter the VPN depends on.
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ℹ
macOS steps
For macOS-specific commands for this issue, use the Terminal equivalents — most fixes use
sudowith the same tool names. The key differences are usingdscacheutil -flushcachefor DNS andnetworksetuporSystem Settingsfor network management.
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1
Confirm your credentials are valid
# Test VPN connectivity manually (OpenVPN example)
sudo openvpn --config /path/to/your.ovpn --auth-retry interact
# Check VPN service logs
journalctl -u NetworkManager -f -
2
Switch the VPN protocol
# Install WireGuard (faster and less likely to be blocked)
sudo apt install wireguard -y
# Or install OpenVPN if not present
sudo apt install openvpn network-manager-openvpn -y
# Restart NetworkManager to pick up new plugins
sudo systemctl restart NetworkManager -
3
Check if a firewall is blocking VPN ports
# Check UFW (Ubuntu's firewall) status
sudo ufw status verbose
# Allow OpenVPN port (UDP 1194)
sudo ufw allow 1194/udp
# Allow WireGuard port (UDP 51820)
sudo ufw allow 51820/udp
# Check iptables rules
sudo iptables -L -n | grep -E "1194|51820|443" -
4
Sync your system clock
# Check current time sync status
timedatectl status
# Enable automatic time sync via NTP
sudo timedatectl set-ntp true
# Force immediate sync
sudo systemctl restart systemd-timesyncd
timedatectl show-timesync -
5
Reinstall the VPN client completely
# Remove and reinstall OpenVPN + NM plugin
sudo apt remove --purge openvpn network-manager-openvpn -y
sudo apt autoremove -y
sudo apt install openvpn network-manager-openvpn network-manager-openvpn-gnome -y
sudo systemctl restart NetworkManager
Still stuck? Enable VPN logging (usually in Settings → Logs) and share the log file with your IT help desk. The log contains the exact error code, which cuts diagnosis time from hours to minutes.