Troubleshooting Connection Errors on Windows PCs
Please try these steps if your VPN connection is not working properly in the MillenVPN app you are using.
① Install the latest version of the app
After uninstalling MillenVPN, download the latest version of MillenVPN and try connecting to the VPN again.
If you already have the latest version of the app installed, please reinstall the app once.
Installing the latest version of the Windows appHere
②Relogin
Please click the Logout button (the second button from the bottom in the left panel of the MillenVPN application) and then log back in.
③ Protocol Change
Please change the "VPN Protocol" setting in the "Connection" tab of the MillenVPN app to either "WireGuard" or "OpenVPN," then try connecting again.
④ Add to Exceptions
- Open the "Windows Defender" section from the device's Control Panel, then click "Allow an app or feature through Windows Defender Firewall."
- As shown in the image below, click either ① "Change Settings" or ② "Allow Another App," then locate the "MillenVPN app" in ③ and click ④ "Add."
- As shown in the image below, "MillenVPN" will be added to the list. Check the box for ⑤ and click ⑥ "OK".
- Return to the screen shown in 1, click "Turn Windows Defender Firewall on or off," and the following screen will appear. Check the box next to "Turn off Windows Defender Firewall" and click "OK."
⑤Changing the settings for UDP ports 500 and 4500
- Log in to MillenVPN and select Settings (gear icon) from the left-hand menu.
- Click the "Connection" tab and check the "VPN Protocol".
- Environment Check
If the VPN protocol is set to "IKEv2" (default), please verify that access to UDP ports 500 and 4500 is permitted in your firewall, security software, or router settings. If access is not permitted, please modify the settings accordingly.
Customers who meet the following criteria should follow the steps in ② Changing the VPN Protocol to switch the protocol to either "WireGuard" or "OpenVPN," then try reconnecting.
- The above steps did not resolve the issue / Changing the settings is difficult
- Unable to modify router settings or verify availability of IKEv2 connections via other devices.
- When connecting, the error message "VPN Connection Failed: Cannot set value to Null. Parameter name: device" is displayed.
⑥ Restart the device
This may be caused by an internal error on your device. Please restart your Windows device and try connecting to the VPN again.
⑦ Trying other connection methods
If you do not see improvement after trying the steps listed in ① to ⑥ above, please refer to the page below to check whether you can connect using "MillenVPN Native" or "MillenVPN Native OpenConnect".
【Getting Started with MillenVPN Native】
https://support.millenvpn.jp/669
【How to Get Started with MillenVPN Native OpenConnect】
https://support.millenvpn.jp/853
Note that, "Unable to connect to the VPN server. If you encounter an error, it is possible that your environment is not configured to allow VPN connections. (If an error code is displayed, it will be 809 or 87.)
Please verify that Windows Defender, the firewall between the client and server, security software, NAT, or the router is not configured to block VPN connections.