Can't connect to VPN (The L2TP connection attempt failed because the security layer)

[Kenn_Val18]

Hi @All 

Can you help me or give me some ideas on how to solve this VPN error on Windows 10: 'The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer'? Some users in our company cannot connect to our VPN when they are on public Wi-Fi or other internet connections, but they can connect using some other networks. We are using a Cisco Meraki MX 17.10.4.

Thank you.

[Jonathan-S]

Hi @Kenn_Val18

Based on the error that you provided, my best guess is that the Internet connection that the client is connecting to is blocking UDP traffic 500 and/or 4500.

My recommendation would be to reach out to our Enterprise Support team in order to troubleshoot further with a client/device who is currently experiencing this issue. You can view the Support options by navigating to Help > Get help, followed by clicking on the "Still need help?" link.