Are you facing the Connection Failed with Error 651 Windows PC Issue? This has been a common error code issue arising in Windows 7 and other systems. It is experienced when you are connecting through PPPoE connections. There are multiple causes for this error code. The most common ones include:
- IP address conflict
- Rasapppoe.sys file being stored in the wrong place
- Registry errors
- Corrupted Windows files
The result can be a frozen PC, potential virus infections and system crashes.
So how can you fix this Connection Failed with Error 651 Windows PC Issue? This guide will help you resolve this issue.
1st Method: Reinstalling the Network Adapter
Follow these steps to reinstall the network adapter:
- Open ‘start’ menu
- Type ‘device manager’ to search for it and open it
- Right click on ‘network adapter’

- Click ‘uninstall’ and then ‘ok’
Once the un-installation is completed, click on ‘scan for hardware changes’. Doing this will help reinstall network adapter
If this is the underlying cause, reinstallation of the network adapter can help in addressing the Connection Failed with Error 651 Windows PC Issue.
2nd Method: Disabling IPv6 Internet Connection
Use the following steps to disable the IPv6 internet connection to fix the Error 651 code:
- Open ‘start’ menu
- Open ‘control panel’ (search for it if it is not already visible)
- Open ‘network and sharing center’
- Open ‘local area connection’
- Click on ‘properties’
- Look for the ‘networking’ section and clear the option against ‘internet protocol version 6 (TCP/IPv6)’
Press OK and it’s done.
3rd Method: Disabling Auto-tuning Feature
You can disable the auto-tune feature using the following steps:
- Open ‘start’ menu
- Type ‘cmd’ or search for ‘command prompt’ and open it
- Type the following: ‘netsh int tcp set global autotunning=disabled

- Type the following: ‘netsh interface tcp show global’ (this will verify if it is disabled)
4th Method: Recreate Dial-Up Connection
If the issue is related to the dial-up connection, you can fix the Connection Failed with Error 651 Windows PC Issue using the following steps:
- Open ‘start’ menu
- Open ‘control panel’
- Open ‘network and sharing center’
- Locate and click on ‘set up a new connection or network’
- Click on ‘set up a dial-up connection’
- Fill up the form
- Click ‘create or connect’
5th Method: Reset TCP/IP
You can also reset TCP/IP to fix the Connection Failed with Error 651 Windows PC Issue. The steps involved are as following:
- Open ‘start’
- Type ‘cmd’ or search for the ‘command prompt’ and open it
- Type the following: ‘netsh int tcp reset resettcpip.txt’
- Hit ‘enter’
When you reset the TCP/IP on your system, it may help in fixing the Error 651 code.
6th Method: Reconnect the Connecting Device
The Error 651 Windows problem may also be fixed by reconnecting the connecting device. So follow the above-mentioned methods to fix this error code. If one method doesn’t work, the underlying cause can be addressed by another method.
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