Hi,
Thank you very much for your feedback.
Please try to modify the value of LmCompatibilityLevel to 3 to see if the client can connect VPN.
The issue occurs may because clients connections are rejected or refused by the server since the NTLM version used are different by the client(NTLM) and server(Only accepts NTLMv2)
Value 3 means clients use only NTLMv2 authentication, and they use NTLMv2 session security if the server supports it. Domain controllers accept LM, NTLM, and NTLMv2 authentication.
Value 5 means clients use only NTLMv2 authentication, and they use NTLMv2 session security if the server supports it. Domain controller refuses LM and NTLM authentication responses, but it accepts NTLMv2.
Please restart Windows to make changes to this entry effective.
For more details please refer to the following article:
Best Regards,
Sunny
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