RestClient Authenticator NtlmAuthenticator not work after upgrade the LmCompatibilityLevel value to 5

[Tony Y Jia]

Hi Team,

Hope you are doing well.

We met an issue after modified the register value to 5 as below for security purpose.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa

LmCompatibilityLevel = 5

We are using the RestClient to send request to service for authorize purpose and the Authenticator was set as below:


RestClient client;

CookieContainer cookie;

client.Authenticator=new NtlmAuthenticator();

client.CookieContainer= cokkie;


It was worked well before we upgrade the register value from 4 to 5.

The value 5 means send NTLMv2 response only and refuse LM& NTLM.

Could you give us some advice how to migrate it from NTLMv1 to NTLMv2 in RestClient request?

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