Windows error 1741 (RPC_S_UNKNOWN_AUTHN

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Description: The RPC runtime does not recognize the authentication type requested by the RPC security operation.

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RPC_S_DUPLICATE_ENDPOINT	RPC_S_MAX_CALLS_TOO_SMALL

RPC_S_UNKNOWN_AUTHN_TYPE

Authentication type must match an RPC security mechanism the runtime understands

RPC_S_UNKNOWN_AUTHN_TYPE is a security-configuration status. RPC bindings can carry authentication service, authentication level, authorization service, credentials, and security quality-of-service settings. These fields are related but not interchangeable.

The status should be distinguished from RPC_S_UNKNOWN_AUTHN_SERVICE and RPC_S_UNKNOWN_AUTHN_LEVEL. One rejects the authentication service identifier, another rejects the protection level, while this status reports an unrecognized authentication type in the relevant operation.

What to inspect

Log symbolic authentication constants, not only numeric values copied from configuration.
Verify that a structure version and its authentication-related fields match the API that consumes it.
When porting DCE RPC code or a custom wrapper, confirm that constants from a different RPC implementation were not passed to Microsoft RPC.
Capture RPC extended error information when the failure arises during security-context negotiation.

Changing the server principal name will not make an unknown authentication type valid. Correct the local security configuration first.

References

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