Error 633: The modem or other connecting device is already in use

error 633

When a user tries to connect to the Internet using a modem, a Wi-Fi network or an ethernet connection and encounter Error 633there are a few things that could possibly go wrong. Reports on this issue date back to the Windows Vista era and have survived even today, affecting hundreds of Windows 10 users. This guide is a snapshot of this well-documented VPN error. Read on to understand that the 633 error is, its symptoms, its causes and its fixes.

The modem (or other connection device) is already in use or is not configured properly

Users affected by this problem see an error message when they try to connect to the Internet. it reads – "The modem or other connection device is already in use or is not configured appropriately." This error message for the 633 VPN error explicitly states that the modem is malfunctioning due to a faulty configuration. Possible causes of this error are:

  • The Miniport WAN device (found in Device Manager -> Network Adapters) associated with your preferred VPN protocol may not work properly.
  • The TCP port required for the VPN connection can be used by another software application.

Sometimes error 633 can occur when multiple Internet connections configured on one device or communication port are being exploited by another application. In addition, the affected modem is not bound to a specific device; therefore, any model and model of PC can be affected.

Fix 633 Errors Under Windows 10

The first solution to correct VPN 633 error is to unplug or shut down the Internet device you used. Once done, try again to connect to the Internet to see if the problem is resolved. If the problem persists, try the following solutions:

  1. Explicitly reserve the TCP port
  2. Use the netstat command to find the program using port 1723 and terminate it
  3. Get rid of irrelevant Internet device programs
  4. Update network card drivers
  5. Uninstall (then reinstall) your network card.

Let's examine these solutions in detail.

1) explicit reservation of the TCP port

Open theRun"Dialog box by pressing"Win + R. '

Enter & #39;regedit& #39; And click & #39;D & #39; agreement'Open a window of the registry editor

In the Registry Editor, locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services Tcpip Parameters

On the & #39;edit & #39; menu, follow the path New> Multi-string value

Rename the value of multiple strings in 'Reserved portsThen double-clickReserved ports. '

In the & #39;Value data"Box, type"1723-1723Then click on 'D & #39; agreement'To save the new value

Quit the Registry Editor and restart your computer.

As soon as the system starts, check if this fix worked.

2) Use the netstat command to find the program that uses port 1723 and terminate it.

Go toThe Start menu»And search for«cmd. '

On the result of the search entitled "cmd& #39; Right-click and choose & #39;Run as an administrator'To launch the command prompt with administrator privileges

In the command prompt window, type 'netstat -onAnd press'ENTER. '

In the displayed output, identify the process ID (PID) of the program, if any, that uses TCP port 1723 on your system.

At the command prompt, type the following, and then press'ENTER & #39;

taskkill /PID PID /F

Once the taskkill command has been executed, the offending program will be forced to close and TCP port 1723 will have been released.

Note: The taskkill command completes the process that corresponds to the process ID number. The / F option is used to terminate the process forcibly.

Type & #39;exit& # 39 ;, then press'ENTER'To exit the command prompt

Restart your system now. Once the computer has started, the felonious program should start using a TCP port other than 1723, leaving the TCP port 1723 free for your Internet device.

3) Get rid of irrelevant Internet device programs

Your modem may not work properly if your system contains irrelevant programs or applications such as an Internet booster, third-party tools that come with the modem, and so on. These programs may not be necessary for your modem or Internet system. Therefore, try to uninstall them. Follow these steps:

  1. From & #39;The Start menu& #39; search & #39;add or remove programs"
  2. Click on the result of the search titled & #39;Add or remove programs"
  3. Find the program in question, right-click on it, and click "uninstall'And follow the uninstallation process

Once the unwanted application has been removed, reboot your system and try to connect to the Internet.

4) Update the drivers of the network card

  1. Press & #39;Win + R& #39; open & #39;Run. '
  2. In the & #39;Run"Dialog, type"devmgmt.mscAnd press'Enter& #39; launch & #39;Device Manager. '
  3. Double click on theNetwork AdaptersSection to enlarge
  4. Locate the network card used by your computer, right-click and select "Update driver software. '
  5. Select 'Automatically search for the updated driverAnd wait for Windows to start the search.

If your system finds updated drivers for your network adapter, it will download and install them automatically. Once done, try to connect to the Internet and see if the problem is resolved.

5) Uninstall (then reinstall) your network adapter

Press & #39;Win + RTo open theRun& #39; Dialogue

In the & #39;Run"Dialog, type"devmgmt.msc ' and press'Enter& #39; launch & #39;Device Manager. '

Double click on theNetwork AdaptersSection to enlarge

Locate the network card used by your computer, right-click and select "uninstall. '

ActivateRemove the driver software for this deviceBy checking the box

Click & #39;D & #39; agreement& #39; to confirm

Wait for the uninstall process to complete, then follow the path, click Action> Find Changes on Hardware have Windows automatically reinstall the network adapter and its drivers.

Once the network card is reinstalled, reboot your system and check if the problem is gone.

I hope this guide has helped you resolve VPN error 633.

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