What does HRESULT 0xC00D28A4 (NS_E_DRM_UNABLE_TO_VERIFY_PROXIMITY) mean?

NS_E_DRM_UNABLE_TO_VERIFY_PROXIMITY

Meaning in the active workflow

The first actionable fact in NS_E_DRM_UNABLE_TO_VERIFY_PROXIMITY is that the timed proximity exchange did not prove that the receiver is sufficiently near the transmitter. The subsystem producing this result is WMDRM for Network Devices, not the media decoder; it performs the transmitter/receiver protocol that registers a network playback device, approves it, validates proximity, opens a protected session and transcrypts licensed content for that receiver.

Start by capturing challenge/response timestamps, retries and network path latency.

Preserve the original generation

The object graph behind this result includes device certificate and serial number, registration-database entry, approval flag, validation timestamp, network session, protocol message and transcrypt policy. A trace should retain the exact WMDRM-ND message type, device identifier, certificate chain, registration state, round-trip timing and the first protocol HRESULT.

This evidence matters because the rejected condition is specifically that the timed proximity exchange did not prove that the receiver is sufficiently near the transmitter.

Confirm the condition

1. Preserve this result and 0xC00D28A4 before cleanup, fallback or another media item changes the context.
2. Compare the failure with a known-good case that changes only the property named by this condition: the timed proximity exchange did not prove that the receiver is sufficiently near the transmitter.
3. Apply the targeted fix: reduce path delay/loss and rerun validation on the local network.
4. Associate it with its current WMDRM for Network Devices object and the requested action.
5. Run the direct check: capture challenge/response timestamps, retries and network path latency.

Failure model

It should be modeled as a failed precondition, not as an arbitrary media exception. Demonstrate the precondition by choosing to capture challenge/response timestamps, retries and network path latency, and remove it by choosing to reduce path delay/loss and rerun validation on the local network. This distinction prevents a license-policy result from being hidden by a later Player dialog and keeps the test attached to the original object instance.

What remains unknown

The timed proximity exchange did not prove that the receiver is sufficiently near the transmitter.

Diagnostic checklist

Compare neighboring states

Operational response

Repair the owner of the check: reduce path delay/loss and rerun validation on the local network.

Technical references

• Windows Media DRM 10 for Network Devices
• Device registration
• Using the WMDRM-ND protocol
• MS-DRMND protocol specification