When you dial your Internet Service Provider (ISP), you receive:
Error 720 - the connection attempt failed because your computer and the remote computer could not agree on PPP control protocol.
If you open Device Manger and expand Network adapters, you may see a yellow exclamation mark (!) over the icon for the WAN Miniport IP (#2) device?
This problem can be caused if any of the following are true:
- The TCP/IP protocol is unbound from the dial-up adapter.
- A second WAN Miniport IP device driver is loaded and it causes a conflict.
To resolve the problem:
01. Open Control Panel and double-click Network and Dial-up Connections.
02. Right-click Local Area Connection and press Properties.
03. Select Internet Protocol (TCP/IP) and press Uninstall.
04. Follow the on-screen instructions.
05. When prompted, restart your computer, but press No if prompted to allow Windows to enable a protocol.
06. Right-click My Computer and press Properties.
07. Select the Hardware tab.
08. Press Device Manager.
09. Use the View menu to Show hidden devices.
10. Expand Network adapters.
11. If there are no WAN Miniport IP devices, go to step 22.
12. Use Regedit.exe to navigate to:
13. Use the Registry menu to Export Registry File. Name it Backup_Network_adapters.reg, just in case you must restore these entries by right-clicking Backup_Network_adapters.reg and pressing Merge.
14. For each sub-key that contains a DriverDesc Value Name whose data value indicates it is a WAN Miniport (IP), right-click the sub-key and press Delete. On all my computers, key 0005 is a WAN Miniport (IP).
15. Exit the Registry Editor.
16. Right-click My Computer and press Properties.
17. Select the Hardware tab.
18. Press Device Manager.
19. Use the View menu to Show hidden devices.
20. Expand Network adapters.
21. For each WAN Miniport (IP), press Uninstall. Press OK to confirm device removal.
22. Open Control Panel and double-click Network and Dial-up Connections.
23. Right-click Local Area Connection and press Properties.
24. Press Install.
25. Select Protocol in the Select Network Component Type dialog and press Add.
26. Select Internet Protocol (TCP/IP) under Network Protocol and press OK.
27. When TCP/IP is installed, press Close.
28. Turn off the power to your modem or shutdown your computer.
29. Turn on the power to your modem or start your computer.
30. Dial your ISP.