What does HRESULT 0x803D0016 (WS_E_PROXY_ACCESS_DENIED) mean?

WS_E_PROXY_ACCESS_DENIED

WS_E_PROXY_ACCESS_DENIED is a Windows Web Services API HRESULT. It means that the proxy refused the request because of an access rule, authentication requirement, content policy, destination restriction, or similar proxy-side control.

Diagnostic discriminator: Repeat only a policy-safe probe through the same proxy while varying the authenticated identity or destination rule under test. If the proxy remains reachable but explicitly denies the request, troubleshoot proxy authorization and policy rather than endpoint connectivity. Preserve the proxy response, target URL and account context without logging reusable credentials.

What to check for WS_E_PROXY_ACCESS_DENIED

• Check proxy authentication, destination allow-lists, user identity and policy logs.
• Confirm that the endpoint URL and transport are allowed for the account and network segment.
• Correct the proxy policy or request configuration instead of silently routing around the proxy.

Microsoft documentation