• If you're running a VPN client through a PPP dial-up connection, you might run into error 734.
  • Check out the guide below and follow the enlisted steps to eliminate this issue and regain web access promptly.
  • Want some more fixes for your VPN situations? Check out VPN Errors & Solutions page.
  • Visit the VPN Guides Hub as well and get the latest tips to maximize the use of your virtual private connection.
     
fix VPN error 734

Error 734 occurs for some users who try to utilize their VPNs with PPP dial-up connections. The full error message states, Error 734: The PPP link control protocol was terminated. Consequently, no VPN connection can be established.

That error can often be due to a misconfigured PPP dial-up connection. Below are a few Windows resolutions that might fix error 734 for most users.

6 quick solutions to fix VPN error 734

  1. Deselect the Negotiate Multi-link for Single Link Connections Option
  2. Install Private Internet Access
  3. Select the Allow Unsecured Password Option
  4. Adjust the Protocol Settings for (PPP) dial-up connection
  5. Fix Registry Conflicts
  6. Switch Off Windows Defender Firewall

How can I fix VPN error 734?

1. Deselect the Negotiate Multi-link for Single Link Connections option

This is the official Microsoft resolution for Error 734. Error 734 can often be due to the Negotiate multi-link for single link connections setting.

Thus, turning multi-link off can often fix this issue. Follow the guidelines below to disable multi-link for single link connections.

  • Press the Windows key + R keyboard shortcut to launch Run.
  • Enter ncpa.cpl in Run and click OK to open the Control Panel applet shown directly below.

  • Right-click the required dial-up connection and select Properties.
  • Select the Options tab.
  • Press the PPP button to open a PPP Settings window.
  • Deselect the Negotiate multi-link for single link connections option on the PPP Settings window.
  • Then press the OK buttons on both windows.

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2. Install Private Internet Access

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3. Select the Allow Unsecured Password option

The Error 734 error message also pops up when unsecured passwords aren’t enabled. Thus, selecting the Allow unsecured password option is another potential resolution (for XP users). This is how XP users can select that option.

  • Open the Start menu, and select Settings > Network and Dial-up Connections.
  • Then right-click the dial-up connection you need and select the Properties option.
  • Then select the Security tab, which includes a Validate my identity as follows drop-down menu.
  • Select Allow Unsecured Password from the Validate my identity drop-down menu.
  • Press the OK button to exit.

4. Adjust the Protocol Settings for (PPP) dial-up connection

  • Some users have confirmed that deselecting most of the protocol settings can fix Error 734. To do that, open the Run accessory.
  • Enter ncpa.cpl in Run, and press the Return key.
  • Next, right-click the dial-up modem and select Properties.
  • Select the Security tab on the Properties window.
  • Select Allow these protocols radio button.
  • Then deselect all the protocol check boxes except Microsoft CHAP Version 2 (MS-CHAP v2). 
  • Windows XP users will need to click Advanced Custom Settings on the Security tab > Settings and then deselect all checkboxes except MS-CHAP v2.
  • In addition, make sure that Type of VPN is configured to Point to Point Tunneling Protocol (PPTP).  
  • Click the OK button.

Windows 10 PPTP VPN is not connecting? Here’s how to fix it.


5. Fix Registry conflicts

Error 743 can also be due to registry conflicts. Thus, cleaning the registry with a registry cleaner utility might fix error 743. This is how users can clean the registry with the freeware CCleaner.

  • Click Free Download on CCleaner’s page to download the software’s setup wizard.
  • Open the setup wizard to add CCleaner to Windows.
  • Launch CCleaner and click Registry.

  • Select all the registry check boxes.
  • Click the Scan for Issues button to scan the registry.
  • Press the Fix selected Issues button to fix the registry.
  • A dialog box opens that asks users if they want to back up their registries. Select Yes to back up the registry if you prefer, and then click Save on the Save As window.
  • Thereafter, press the Fix All Selected Issues button to repair all the issues.

6. Switch off Windows Defender Firewall

  • In addition, switch off the Windows Defender Firewall to ensure that it isn’t blocking connections. Users can do that in all Windows platforms by entering firewall.cpl in Run’s Open text box.

  • Click Turn Windows Defender Firewall on or off to open the firewall settings below.

turn off firewall windows 10

  • Click both the Turn off Windows Defender Firewall radio buttons to switch off WDF.
  • Press the OK button to exit.

So, error 734 is more of a dial-up connection error than a VPN issue. These solutions might help you fix it so that you can utilize your VPN with PPTP.

Let us know how it worked for you in the comments section below.

FAQ: Learn more about protocols and VPNs

  • How do I fix PPP link control protocol was terminated?

The official resolution provided by Microsoft is to disable multi-link for single link connections. To do this, open the Control Panel and right-click the dial-up connection. Then, select Properties->Options->PPP and uncheck the Negotiate multi-link for single link connections option.

  • Is dial up secure?

It is as secure as other types of connections such as ADSL, Ethernet cable, and so on. Pairing it with a VPN tool optimized to support this protocol such as PIA can improve the speed of your connection and enhance your online security.

  • What is the best protocol for VPN?

The open-source OpenVPN is the fastest and most flexible protocol, thus the preferred choice for VPN routed connections. Nevertheless, most premium VPNs support a wider range of protocols with decent performances.

Editor’s Note: This post was originally published in December 2018 and has been since revamped and updated in May 2020 for freshness, accuracy, and comprehensiveness.