Working with Error 720 related to Dial-Up Networking in Thinkpad

[connoisseur]

I need urgent help for fixing a error. It shows as Error 720 Dial-Up Networking could not negotiate a compatible set of network protocols. What does this error refers to. I am not able get my internet connection work because of this. Anyhow I tried to contact my service provider for the issue, but they said the error is from my end. What should I do know. Will formatting my system completely and restoring Windows will do the job. Thanks.

[Kakashi Hatake]

The issue occur when the laptop modem is not able to create a proper connection with the remote network. To fix the issue you will need to edit Windows registry. So before doing that you must first have a backup of the same. So in case of any error you can just restore that back again. Many a time re-installing the Wan port can fix the issue. You can try to do that from device manager. If your system was working fine before then you can try running system restore to get the working settings.

[Ebadaah28]

The issue is related to your laptop modem. Right click on My Computer > Manage > Device Manager. Just check that your Wan miniport is installed or not. Is there any exclamation mark on the same. You can right click on that and choose update drivers.

[Rance]

Here are some steps that can help you to fix the issue. First as the method shown above go in Device Manager and unintsall the Wan miniport. Remove it completely and do not reboot your system. Now click on Start > run > regedit. On that location the following : HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318}. Check each folder inside that. You will need to find something similar to Wan miniport. You will need to delete the associate key which is shown on the right side. Exit it and reboot your system. Re-install the tool and then check back. I think you might need to repeat the steps a number of time check that all devices are uninstall first properly and then they are back installed.

[Aaryan2011]

It is necessary to clean the associated keys when you remove the hardware. For that I think you can try out any free registry cleaners like CCleaner. I had seen a number of time because of invalid registry files many process in Windows are affected. You might need to figure out first which key to remove.

[Swiz]

Below is number of reference which can guide you for the issue. I think there are many steps in the link below you can use and fix the issue. The first thing which I will also recommend you is to install and re-install the hardware associated to Wan miniport back again. There will be a number of hardware in Device Manager. You can update the drivers and check once again whether your dialer is responding or not.

Troubleshooting network and dial-up connections

[Caelyn]

Did you checked properly that your internet line is active. Dailer creates error when your devices is not able to register your system on network. This is a common issue which is mostly from the isp end.