Getting an error when connecting to VPN "The L2TP connection attempt failed .."

AVN 20

Hi,

I am having an error when conencting to VPN, "The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer." It's weird because I was just able to connect last week, all of a sudden it is having this error.

I just installed Windows 11 hoping that it would be solved but did not at all (I had Windows 10). Last update was 07/14/2023, but I was able to connect to the VPN between 07/15/23-07/27/23, then the latest update would be 08/01/2023, so unsure if this is an update issue?

Any help would be appreciated,

Thank you

Will 425 Reputation points

2023-08-02T19:53:29.7133333+00:00
Are you configuring this with the VPN via the Windows OS?

Or are you using a 3rd party VPN client?

If its the OS

Search > VPN

For your VPN connection, click on Advanced Options

Go to More VPN Properties and click Edit

Click the Security tab

Under Authentication, ensure the Allow these protocols

Depending on what your corporate VPN requires, ensure the correct one is enabled. I've seen it where this default to MS-CHAPv2 when the network needs it to be PAP.

Also the other thing to check if it suddenly stopped working, also seen this happen:

For your VPN connection, click Edit

Look at the Type of sign-in info, it maybe defaulted to General authentication method where you need something like Username and Password
AVN 20 Reputation points

2023-08-02T21:17:48.4066667+00:00

Hi Thank you for your response. Yes, it is the Windows OS VPN.

I don't see 'More VPN Properties' when I click on 'Advance Options'?
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Will 425 Reputation points

2023-08-03T00:40:13.98+00:00

Take the elevator one level up ;)
Will 425 Reputation points

2023-08-03T00:42:06.12+00:00

Take the elevator one level up :)
AVN 20 Reputation points

2023-08-03T17:06:59.4666667+00:00

Hi thank you for your response again!

Yes I clicked that button, but I can't seem to find the 'Security' tab under it?
Will 425 Reputation points

2023-08-03T19:32:39.2666667+00:00
Sorry, think I missed a step

Advanced Options > More VPN Properties (Edit)

Click Security Tab

Check that the correct Protocols are selected/enabled.
AVN 20 Reputation points

2023-08-03T20:42:35.26+00:00

Hi,

For some reason the 3rd option is not showing up 'More VPN Properties..' and just ends at the Proxy Settings option :(
Will 425 Reputation points

2023-08-03T23:10:45.74+00:00
That's screenshot indicates W10 or W11 so I'm not sure why that's not there. Wow OK. Let's switch gears then.

Go to Search, type network

Select View Network Connections

You'll see a list of your configured network connections including your VPN connection

Right click and go to Properties

You should now see the window you would have seen in the previous instructions.

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Getting an error when connecting to VPN "The L2TP connection attempt failed .."

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