HRESULT 0x803D001B (WS_E_PROXY_REQUIRES_NEGOTIATE

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Description:

the HTTP proxy requires Negotiate authentication.

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WS_E_PROXY_REQUIRES_NTLM_AUTH	WS_E_SERVER_REQUIRES_BASIC_AUTH

WS_E_PROXY_REQUIRES_NEGOTIATE_AUTH

WS_E_PROXY_REQUIRES_NEGOTIATE_AUTH is a Windows Web Services API HRESULT. It means that the proxy rejected the offered authentication scheme and requires HTTP Negotiate authentication, which can select Kerberos or NTLM depending on the environment.

What to check for WS_E_PROXY_REQUIRES_NEGOTIATE_AUTH

Verify proxy SPNs, DNS, ticket availability and the process identity used for integrated authentication.
Confirm that the proxy is trusted before allowing integrated credentials to be presented.
Inspect authentication logs to distinguish Kerberos configuration failures from fallback behavior.

Microsoft documentation

Diagnostic interpretation

This result has the HRESULT value 0x803D001B. AllStat records the condition as “The HTTP proxy server requires HTTP authentication scheme 'negotiate'.”.

Evidence to capture

Capture any IErrorInfo text, activity identifier, event-log entry, and subsystem trace that mentions this result or the ws / proxy / requires / negotiate / auth operation.
check the documented return contract of the specific API because the same HRESULT can require different recovery in different interfaces.

Retry and recovery

For WS_E_PROXY_REQUIRES_NEGOTIATE_AUTH, recovery should change one confirmed condition at a time. The verification run should use equivalent inputs and prove that the same boundary no longer rejects the operation.

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