Why doesn't NetMeeting work with the built-in modem (for the analog telephone line)?

Why doesn't NetMeeting work with the built-in modem (for the analog telephone line)?
or
When I connect my computer to the Internet using the built-in modem (for the analog telephone line) and execute [NetMeeting], I cannot communicate normally. Why is that so?

When your computer is connected to the Internet with the built-in modem (for the analog telephone line), you should be able to communicate through [NetMeeting] without any problem as a global IP address is set to your machine.

1) If communication cannot be performed through [NetMeeting] normally using the built-in modem, firstly check if you are able to connect to the Internet.

2) If you encounter problems even though you are able to connect to the Internet normally, contact your Internet Service Provider.

3) If you cannot connect to the Internet normally, check if the settings for Internet connection have been done properly.