The connection established does not satisfy the rules of Network address translation (NAT).

You are using a duplicate version of the key or VPN certificate. How to Fix The L2TP Connection Attempt Failed Error on Windows 10 Method 1: Run Network Troubleshooter Method 2: Repair Corrupt Files Method 3: Run Commands to Start Few Services Method 4: Enable MS-CHAP v2 Protocol Method 5: Enable Link Control Protocol Extensions Method 6: Restart Essential Services Method 7: Update Windows Method 8: Disable Antivirus Temporarily (If Applicable) Method 9: Disable Windows Firewall (Not Recommended) Method 10: Reset TCP/IP Configuration Method 11: Create New Registry Entry Method 12: Create UDPE Encapsulation Registry Key Method 13: Manually Forward Ports Method 14: Reinstall VPN Adapter Method 15: Roll Back VPN Adapters Method 16: Uninstall Recent Security Updates You are advised to analyze the reasons one by one and check which of these below-mentioned reasons has caused the issue. We have gathered much data from several users and online reports and so devised a set of reasons that cause the discussed issue. How to Fix The L2TP Connection Attempt Failed Error on Windows 10 #

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