[Solved] Error 651 – Connection Failed with Error 651 in Windows

It is possible that you might have faced error 651 on your computer if you are a Windows user. It is a common problem faced by many Windows users (Especially for Windows 10 users). So before we get into the topic, first let’s see why this error occurs.

Why Error 651 occurs?

Error 651 is a common Windows error which usually occurs when we try to establish an internet connection using PPPoE connections. This error occurs due to various reasons such as:

  • Raspppoe.sys file has been saved in the wrong location.
  • Registry errors.
  • IP address conflict.

If this error occurs, then you might see this message Error 651: The modem (or the other connecting device) has reported an error and usually the message will be titled as “Connection failed with error 651”.

So how to solve this error? well, there is no official solution to fix this error, but there are some common troubleshooting methods which worked for many users. I have collected some of the best working solutions that will help you to solve this error.

Also Read – Fix dns_probe_finished_bad_config Error

How to Fix Connection Failed with Error 651 in Windows

I have compiled a list of solutions that I have collected from various forums and help centers, all these solutions worked for many people and I’m sure that one of below solution will definitely work for you. So let’s start from basic troubleshooting steps to advance one.

1 – Reconnect Your Router or Other Connecting Device

This is the most basic troubleshooting step, One can simply solve this error by reconnecting the internet connecting device. So if you are using router then simply turn off your router and after 5 minutes turn it on or if you are using LAN connection then unplug the wire and plug it back.

2 – Reset TCP/IP On Your PC

Resetting the Windows networking stack can solve error 651 and luckily Windows 8/10 comes with a built-in tool you can use to do this just follow the below steps.

  • Launch command prompt with administrative right.
  • Copy the command given below and hit enter

netsh int ip reset reset.log 

  • Restart your computer and hopefully, the problem will be solved.

3 – Recreating Dial-Up Connection

Your internet connecting device might get hanged during the connection. So recreating your dial-up connection can fix this issue. So simply right click your Dial-Up or Broadband connection and select create copy and then delete your existing connection. Confused? Just follow the step by steps guide given below.

  • Open Network & Sharing Center and click on Change Adapter Setting.
  • Now right click your broadband or dial-up connection and select Create Copy.

Fix error 651 - solution 4

  • This will create a copy of your existing connection.
  • Now simply delete your old connection and redial the new connection.

4 – Disable Auto Tuning Feature

Windows Auto tuning feature is used to improve the performance of programs which receives TCP data from a network. If you are using a router then this method can do the magic, Follow the below steps to disable the auto-tuning feature.

  • Launch command prompt with administrative rights.
  • Copy the below command and paste it in command prompt

Netsh interface tcp set global autotuning=disabled

  • Now just try to restart/reconnect your internet connection.

5 – Disable IPv6 of your Internet Connection

This solution worked for many users. You can simply disable IPv6 to fix this error. Follow the below guide to disable IPv6.

  • Open Control Panel.and select Network & Internet.
  • Further, choose the Network & Sharing Center option.
  • Now click on your active network connection.

Fix error 651 - solution 5

  • Select Properties and switch to Networking tab.

  • Untick/Uncheck Internet Protocol version 6 (TCP/IPv6) and click on Ok.

6 – Reinstall Network Adapter

This is the most working troubleshooting step when it comes to an internet connection problem. You can simply reinstall the network adapter to fix Connection Failed with Error 651 problem. Just follow the below guide to reinstall network adapter.

  • Go to Start and search for devmgmt.msc.
  • Double click it to launch device manager, Now look for Network Adapters Category and click the “+” icon it’s left.

  • Now right-click the first network adapter and select uninstall.
  • Restart your computer and your network adapter will get automatically reinstalled.

7 – Re-register “raspppoe.sys” File

You may face error 651 due to “raspppoe.sys” file fails to load while connecting to the internet. So to fix this you can try re-registering the raspppoe.sys file.

  • Open the command prompt with administrative rights.
  • Now type the following command and press enter.
    regsvr32 raspppoe.sys
  • This command will re-register the raspppoe.sys file which indirectly causes error 651.

8 – Perform Clean Boot

If there is a problem in windows services then performing a clean boot can fix your problem, to perform a clean boot we simply need to disable all other services. Simply follow the below guide to perform a clean boot on your computer.

  • Go to the Start menu and search for msconfig.exe
  • Click it to launch windows configuration.
  • Now under general tab click on Selective startup and select Load startup items

  • Now switch to Services tab and check Hide all Microsoft services.
  • After that just click on Disable all to disable all other services.

Fix error 651 - solution 7

  • Now simply just restart your pc to perform a clean boot.

Watch Video Tutorial

Frequently Asked Questions for Error 651?

What is Error 651 On Internet Connection?

Error 651 on Internet Connection indicates that there is some issue with your modem device. This error usually occurs on Windows devices. Reason for occurring error 651 could be incorrect IP configuration or network card driver issue

What is WAN Miniport PPPoE Error 651?

PPPoE stands for Point to Point Protocol over Ethernet. This error occurs when a user tries to connect Windows 7 with an internet connection. It occurs because of a weak network connection.

How Do I Fix PPPoE Connection?

To fix the PPPoE Connection, you need to pay a visit to control panel settings of your Windows PC. Under the settings “Network and Sharing Center”, select broadband (PPPoE) and fix it.

What To Do When The DNS Server Isn’t Responding?

When DNS server isn’t responding, you should first try restarting your computer. If it doesn’t help, check your router configuration and settings. Eventually, you may reset the router to the default settings.

I hope the above solutions helped you in solving error 651, If not then it might be your ISP’s issue, you should immediately contact your internet service provider (ISP) and report this issue.


  1. Thank you, thank you, thank you! After a Windows 10 install, I ignored your instruction about restarting the router because my tablet was connected. Weeks later, out of sheer frustration, I restarted the router. Worked beautifully! Sorry for ever doubting you.

  2. Found the simple solution! Just click open the Bluetooth switch! Recent windows 10 update caused my laptop unable to connect to the wifi.

  3. Just helped a friend fix this on his W10 laptop. He had an unused dial-up phone modem on his laptop. Uninstalled it and rebooted and started working.

  4. Thanks very much – no.2 (which was proposed by other websites too) did the trick for us. We were re-establishing wifi after dad received new router and Windows 10 didn’t adjust to it.

  5. #2 Worked for me – thank you so much! Lost internet connectivity after hard power outage. Tried multiple things then found this site. Keep up the fine work!

  6. New MB/Processor with same HDD’s from previous MB, and internet is physically in the CAT-5 port, yet system says not connected. 651 error on all attempts. Suggestions?

  7. Great Article. Uninstalling the Network Adapter and restarting the PC worked liked a charm for my DLINK DSL-2730U Modem Router. This was my first installation sequence, thanks a lot Abhishek.


Please enter your comment!
Please enter your name here