If you are trying to connect to the internet using a Wi-Fi, Ethernet or a Wi-Fi connection and you suddenly encounter Error 633, then read on as this post will guide you on how you can fix this problem in your Windows 10 computer.

According to users who encountered the same problem, when they try to connect to the internet, an error pops up that states, “The modem or other connecting device is either already in use or not appropriately configured”. This error is the VPN Error 633 which indicates that the modem is malfunctioning due to some broken configuration. It is possible that this broken configuration is caused by the WAN Miniport device which is associated with your preferred VPN protocol. It could also be due to the TCP port that’s required for the VPN connection to work might be used by another application.

There are instances when Error 622 could occur when there are multiple internet connections set up on one device or when the communication port are exploited by another program. It could also occur when the affected modem is not bound to one specific device. Thus, any model and computer can be affected by this problem.

The first and basic thing you can do to fix the VPN Error 633 is to turn off or unplug the modem your computer is using and then plug it back in to see if the problem is fixed. If not, then there are several other potential fixes you need to check out to resolve the problem. You can try the suggestions provided below and see if any of them help.

Option 1 – Run the Network Adapter Troubleshooter

  • Open the Search bar on your computer and type in “troubleshoot” to open the Troubleshoot settings.
  • Next, scroll down and select the “Network Adapter” option from the right pane.
  • Then click on the Run Troubleshooter” button.

  • After that, your computer will check for any possible errors and will pinpoint the root cause of the problem if possible.

Option 2 – Try to explicitly reserve the TCP port

The next thing you can do to fix the error is to reserve the TCP port explicitly and to do that, follow the steps below.

  • Tap the Win + R keys to pull up the Run dialog box and type “regedit” in the field and hit Enter to open the Registry Editor.
  • Next, navigate to this registry path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
  • After that, follow the path New > Multi-String Value on the edit menu and rename the multi-string value as “ReservedPorts” and then double click on it.
  • Now in the value data of ReservedPorts, input “1723-1723” and click OK to save the changes made.
  • Close the Registry Editor and restart your PC. Once your computer has restarted, check if the VPN Error 633 is fixed or not.

Option 3 – Try to use the netstat command

  • In the Windows Start Search, type “cmd” and from the search results that appear, right-click on Command Prompt and then select the “Run as administrator” option.
  • After opening Command Prompt as admin, type this command and hit Enter: netstat –aon
  • After that, an output will be displayed and from there, look for the process ID or PID of any program that uses the TCP port 1723 on your computer.
  • Next, type this next command and hit Enter: taskkill /PID PID /F
  • Once the command has been executed, the concerned program will be forced to close and the TCP port 1723 will be freed up. Keep in mind that the taskkill command ends the process corresponds to the process ID number and the given command above, “/F” option is used to end the program’s process forcefully.
  • Now restart your computer and after that, the concerned program should start using a TCP port other than 1723 which leaves the TCP port 1723 free for your internet device to use.

Option 4 – Remove any irrelevant internet device programs

You could also try removing any irrelevant device programs since it is possible that any of these programs could be the one that’s causing the modem to malfunction. These irrelevant programs could be an internet booster or third-party tools that comes with the modem and so on. These programs are not necessarily needed for your modem to function. Thus, if you want to fix the VPN Error 633, you can try uninstalling them and see if it fixed the error.

Option 5 – Update the Network Adapter drivers

You might also want to update the Network Adapter drivers by following these steps:

  • Tap the Win + R keys to launch the Run window and then type in the “devmgmt.msc” command and hit Enter to open the Device Manager window.
  • Under the Device Manager, you will see a list of drivers. From there, look for the Network Adapters and expand it.
  • Then right-click on each one of the Network drivers and update them all.

  • Restart your PC and see if it helped in fixing the BSOD error.

Note: If updating the network drivers didn’t help in fixing the VPN Error 633, you can also try to uninstall the very same drivers and restart your Windows 10 PC. After that, the system itself will reinstall the drivers you just uninstalled. Alternatively, you can also download and install the drivers from the manufacturer’s website directly.

To reinstall the network adapter driver, refer to these steps:

  • Open the Devices Manager from the Win X Menu.
  • Then locate the device drivers and right-click on them to open the Properties.
  • After that, switch to the Driver tab and click on the Uninstall Device button.
  • Follow the screen option to completely uninstall it.
  • Finally, restart your computer. It will just reinstall the device drivers automatically.

And that’s how you fix the VPN Error 633 in your Windows 10 computer. For other system-related problems, you can use Advanced System Repair. This program is known as Advanced System Repair and is a useful tool that could repair corrupted registries and optimize your PC’s overall performance, including high CPU usage of some program in your system. Aside from that, it also cleans out your computer for any junk or corrupted files that help you eliminate any unwanted files from your system. This is basically a solution that’s within your grasp with just a click. It’s easy to use as it is user-friendly. For complete set of instructions in downloading and using it, refer to the steps below.

Perform a full system scan using ASR. To do so, follow the instructions below.

  1. Turn on your computer. If it’s already on, you have to reboot

  1. After that, the BIOS screen will be displayed, but if Windows pops up instead, reboot your computer and try again. Once you’re on the BIOS screen, repeat pressing F8, by doing so the Advanced Option shows up.
  1. To navigate the Advanced Option use the arrow keys and select Safe Mode with Networking then hit
  1. Windows will now load the Safe Mode with Networking.
  1. Press and hold both R key and Windows key.

  1. If done correctly, the Windows Run Box will show up.
  1. Type in the URL address in the Run dialog box and then tap Enter or click OK.
  1. After that, it will download the program. Wait for the download to finish and then open the launcher to install the program.
  1. Once the installation process is completed, run ASR to perform a full system scan.

  1. After the scan is completed click the “Fix, Clean & Optimize Now” button.