What does Windows error code 1726 (RPC_S_CALL_FAILED) mean?

RPC_S_CALL_FAILED

RPC_S_CALL_FAILED means that an RPC call failed after the server was reachable at some point. The server procedure may already have started, so the client cannot infer that the operation had no effect.

Important consequence

For state-changing operations, do not blindly retry. First determine whether the server completed the work, partially completed it, or rejected it. Design requests with an idempotency key or an application-level status query where retries are necessary.

What to collect

• The interface and procedure being called, without exposing sensitive arguments.
• Whether the failure followed a timeout, cancellation, connection reset or server restart.
• Extended RPC error records and server-side logs from the same time window.

Microsoft: RPC Return Values · Understanding Extended RPC Error Information