[Solve] Error 633: The modem ( or other connecting device) is already in use or is not configured properly.

Most of people will restart their computer to rid from this error. Errors or problems in modem or connections to modem will make this problem. Also Windows errors may cause to this problem. However, log off or disconnecting and reconnecting of modem with new USB ports will not solve this problem.

How to fix this error ?

Remove and add modem driver : This method is the best and 99% working solution to solve this error without restarting your computer.

Firstly open ‘Control Panel’. (Make sure icons are large or small instead of category, learn more here)
Look for ‘Phone and Modem’ and open it. If you are first time to open this setting, then you have to select a location and type any area code.
Then go to ‘Modems’ menu tab.
Now you can see a list modems. Select your current using modem, and then click on button ‘Remove’.
Click on ‘OK’ button from confirmation message box.
Now click on ‘Add’ button.
Now ‘Add Hardware Wizard’ window will open.
Now Windows will automatically install modem driver from your connected modem. (Here modem already contains its drivers, or you have to install separate drivers for your modem)
After successful installation of modem driver, click ‘Finish’ button.
Now try to connect to internet. You can connect successfully… sure.