Knowledge

RPC_S_INVALID_ENDPOINT_FORMAT - 1706 (0x6AA)

The endpoint format is invalid.

Updated: Feb 21, 2026

Technical Background

The RPC_S_INVALID_ENDPOINT_FORMAT error is a specific error code in the Remote Procedure Call (RPC) subsystem of Windows. It indicates that an endpoint format provided to an RPC function or service was not valid according to the expected format.

Error Details

  • Error Name: RPC_S_INVALID_ENDPOINT_FORMAT
  • Numeric Code: 1706
  • Hex Code: 0x6AA
  • Short Description: The endpoint format is invalid.

This error typically occurs when an application attempts to make a remote procedure call using an endpoint that does not conform to the required format. The RPC subsystem relies on correctly formatted endpoints to establish and maintain communication between local and remote processes or services.

Common Causes

  • Invalid Parameter Values: An incorrect or malformed string was passed as the endpoint parameter to an RPC function.
  • Incorrect Object Type: The object being referenced is not of the expected type for an RPC endpoint, such as a network address or service name.
  • Unsupported Operations: The operation attempted by the application is not supported with the provided endpoint format.

Real-World Context

In practical scenarios, this error can occur when:

  • A client application attempts to call a remote procedure using an incorrectly formatted URL or IP address.
  • An application tries to use an RPC service that requires a specific type of endpoint but is given an incompatible one.
  • The configuration of the RPC service does not match the expected format for the endpoint provided by the client.

Is This Error Critical?

The criticality of this error depends on the context in which it occurs. If the application relies heavily on successful remote procedure calls, then encountering this error can be critical as it may prevent the intended functionality from being executed. However, if the application is designed to handle such errors gracefully, the impact might be minimal.

How to Diagnose

To diagnose and resolve RPC_S_INVALID_ENDPOINT_FORMAT, follow these steps:

  1. Review Operation Context: Ensure that the operation context in which the RPC call is made is appropriate for the service being accessed.
  2. Validate Parameters: Check the parameters passed to the RPC function, particularly the endpoint format. Ensure they are correctly formatted and match the expected input type.
  3. Confirm Object Types: Verify that the object types used as endpoints (e.g., URLs, IP addresses) are correct and compatible with the service being called.
  4. Verify Input Data: Validate any additional data or configuration settings related to the RPC endpoint format.
  5. Check Limits or Constraints: Ensure that there are no system limits or constraints that could affect the validity of the endpoint format.

How to Resolve

To resolve RPC_S_INVALID_ENDPOINT_FORMAT, consider the following actions:

  • Correct any invalid parameter values and ensure they conform to the required format.
  • Adjust the operation context if necessary, ensuring it aligns with the expected usage scenario for the RPC service.
  • Restore or modify configuration settings related to endpoint formats as needed.
  • Retry the operation with valid inputs and correct formatting.

Developer Notes

Developers should ensure that their applications handle RPC_S_INVALID_ENDPOINT_FORMAT errors gracefully. This can involve providing user-friendly error messages, logging the issue for further analysis, or implementing fallback mechanisms to maintain application functionality even when an invalid endpoint is encountered.

Related Errors

  • RPC_S_NO_CONTEXT_MISMATCH: Indicates a mismatch in context between client and server during an RPC call.
  • RPC_S_CALL_FAILED: General failure of an RPC call that may not specify the exact reason for the failure.
  • RPC_S_INVALID_BINDING: An invalid binding format was provided, which is similar to but distinct from RPC_S_INVALID_ENDPOINT_FORMAT.

FAQ

Q: What does RPC_S_INVALID_ENDPOINT_FORMAT mean?

A: It indicates that an endpoint provided to an RPC function or service is not in the correct format.

Q: How can I prevent this error?

A: Ensure that all endpoints passed to RPC functions are correctly formatted and match the expected input type. Validate parameters before making RPC calls.

Q: Can this error occur due to network issues?

A: While network issues might indirectly contribute, RPC_S_INVALID_ENDPOINT_FORMAT specifically relates to endpoint format validation rather than network connectivity.

Summary

The RPC_S_INVALID_ENDPOINT_FORMAT error is a specific and critical issue in the RPC subsystem of Windows. It highlights the importance of correctly formatted endpoints for successful remote procedure calls. By understanding its causes and following diagnostic and resolution steps, developers can ensure robust and reliable application behavior when working with RPC services.