Broadband connection Error 720 causes:ADSL dial when encountered 720 error is a very depressing thing, the meaning of this error: Network protocol failure, resulting in a total of two of the reasons for this failure, so we also divided into two ways to solve. Broadband connection Error 720 solution: (i) ADSL ISP server failure, abnormal shutdown caused network protocol error, at this time need to call the ISP inquiries, remove all network components reinstall network. Two XP system automatically updated, TCP/IP error, local loop can not ping, ADSL dial-up authentication user name and password prompted 720 error. Workaround: Open the control plate, Add/Remove Programs, uninstall system upgrade patches 893066 and 890923, if not this upgrade patch will be all the patches uninstalled. Broadband connection Error 720 phenomenon common in the XP system, the system is generally restarted, can be dialed many times, 90% can be resolved.