Knowledge

RPC_S_INVALID_AUTH_IDENTITY - 1749 (0x6D5)

The security context is invalid.

Updated: Feb 21, 2026

Technical Background

The error code RPC_S_INVALID_AUTH_IDENTITY is a specific error code in the Remote Procedure Call (RPC) protocol, indicating that an invalid security context was encountered during authentication. This error typically arises when there are issues with the authentication credentials or the security context used for RPC operations.

Error Details

  • Error Name: RPC_S_INVALID_AUTH_IDENTITY
  • Numeric Code: 1749 (0x6D5)
  • Short Description: The security context is invalid.

This error suggests that the authentication mechanism failed to establish a valid security context, which is essential for secure RPC communication. It can occur due to various reasons such as incorrect credentials or limitations in the supported authentication mechanisms.

Common Causes

  1. Incorrect Authentication Credentials: Invalid or expired user credentials may lead to this error.
  2. Unsupported Authentication Mechanism: The requested authentication method might not be supported by the server or client.
  3. Security Context Issues: Problems with the security context, such as incorrect initialization or corruption, can result in this error.

Real-World Context

This error is commonly encountered in scenarios where RPC services are used for inter-process communication (IPC) or networked applications requiring secure authentication. It may also appear when integrating legacy systems that rely on specific authentication protocols.

Is This Error Critical?

The criticality of this error depends on the application and its security requirements. In environments with strict security policies, this error could indicate a significant security breach or misconfiguration.

How to Diagnose

  1. Review Operation Context: Ensure that the RPC operation is being performed in an appropriate context.
  2. Validate Parameters: Check for any invalid parameters that might be causing the authentication failure.
  3. Confirm Object Types: Verify that the correct object types are being used, as some operations may require specific security contexts.

How to Resolve

  1. Correct Parameter Usage: Ensure that all credentials and authentication parameters are correctly specified.
  2. Adjust Operation Context: If necessary, adjust the operation context or use a different authentication mechanism supported by both client and server.
  3. Restore Data: In cases of corruption, restore the security context data.

Developer Notes

Developers should ensure that their applications handle this error gracefully and provide appropriate feedback to users. Implementing robust authentication mechanisms and validating credentials can help mitigate this issue.

Related Errors

  • RPC_S_ACCESS_DENIED: Authentication failure due to insufficient permissions.
  • RPC_S_INVALID_BINDING: Invalid binding parameters for RPC operations.

FAQ

Q: What does the error code RPC_S_INVALID_AUTH_IDENTITY mean?

A: It indicates that an invalid security context was encountered during authentication in an RPC operation.

Q: How can I prevent this error from occurring?

A: Ensure that all credentials and parameters are correctly specified, and use supported authentication mechanisms.

Summary

The RPC_S_INVALID_AUTH_IDENTITY error code is a specific indication of invalid security context issues during RPC operations. Understanding its causes and implementing appropriate measures can help in resolving such errors effectively.