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RTC_E_STATUS_CLIENT_LENGTH_REQUIRED
Operational meaning: RTC_E_STATUS_CLIENT_LENGTH_REQUIRED
This result marks a specific boundary in a peer, proxy, registrar, or gateway returning a specific SIP response to the RTC transaction: the server requires an explicit Content-Length body framing it received; treating it as a generic RTC failure loses the state needed to choose a safe next action.
For correlation, retain 0x80EF019B in the RTC SIP-status facility carrying status 411 together with this result; for this HRESULT, generic HRESULT text can otherwise hide the protocol family and the exact RTC branch.
Evidence for this HRESULT should show that you inspect the serialized message boundary, Content-Length header, byte count after encoding, and transport; the diagnostic distinction for this HRESULT is that Length Required is a framing problem, not proof that the content itself is invalid.
Signals worth preserving
Do not wait for a generic failure notification to log this result; preserve the API call or event producing it together with the RTC object and transaction state visible at that moment.
- Code-specific proof for this HRESULT: inspect the serialized message boundary, Content-Length header, byte count after encoding, and transport.
- Correlation key for this HRESULT: status-specific headers.
- Protocol or object snapshot for this HRESULT: retry or alternate-target decision.
- Last completed transition for this HRESULT: request method and Request-URI.
- Expected output for this HRESULT: responding Via hop.
For privacy-safe analysis of this result, preserve protocol structure rather than payload content; for this HRESULT, authentication values, complete addresses, buddy lists, and bodies should be redacted or hashed under policy.
Protocol and object boundary
| RTC area | SIP final response boundary |
|---|---|
| Condition to prove | the server requires an explicit Content-Length body framing it received |
| Objects to correlate | SIP request method, client transaction, response status, dialog identifiers and method-specific headers |
| Safe corrective direction | fix serialization so the length matches the transmitted octets and resend as a new valid request |
The surrounding protocol rule for this HRESULT is that The facility code preserves the SIP status number; diagnosis should start with the method and responding hop rather than treating every value as a local COM failure; in addition, the path requires that Some responses invite a modified request or authenticated retry, while others are terminal for the current target or even global for the addressed user.
Verification workflow
- Start from
0x80EF019Band it, then find the method/event pair that first exposed it. - check whether the failure was local before transmission, produced during RTC state validation, or mapped from a remote response.
- the proof step is to inspect the serialized message boundary, Content-Length header, byte count after encoding, and transport.
- keep the analysis at the right boundary: Length Required is a framing problem, not proof that the content itself is invalid.
- after you fix serialization so the length matches the transmitted octets and resend as a new valid request, repeat the smallest reproducer rather than restarting the entire application environment.
The result diagnosis is strongest when object state and protocol trace share timestamps and transaction identifiers; when diagnosing it, avoid treating packet capture and HRESULT logging as substitutes for one another.
Do not confuse it with
Use the following contrast when classifying it: 413 says the body is too large even when correctly framed; for this HRESULT, similar subsystem names do not imply identical recovery.
RTC_E_STATUS_CLIENT_UNAUTHORIZED | the user agent server or registrar requires end-server authentication |
|---|---|
RTC_E_STATUS_GLOBAL_BUSY_EVERYWHERE | the user is busy at every known location and further branching should stop |
RTC_E_STATUS_CLIENT_PROXY_AUTHENTICATION_REQUIRED | an intermediary proxy requires authentication before forwarding the request |
Facility equality is not semantic equality; route each contrasted value through its own recovery branch.
Recovery and control flow
The appropriate response to it is not a blanket reconnect. Instead, fix serialization so the length matches the transmitted octets and resend as a new valid request, while preserving ownership of cleanup and any bounded retry.
A retry after it is safe only after the prior transaction’s outcome is reconciled; after it, reissuing state-changing requests while the peer result is unknown can create contradictory RTC state.
Example for this HRESULT: A custom SIP sender omits Content-Length on a request body accepted by neither the proxy nor the endpoint.
Actions that do not address this condition
- An investigation should not do not retry every 4xx or 5xx response with the identical request.
- also do not show a reason phrase as trusted server identity or authorization evidence.
- Do not translate it into a broad “connection failed” label before preserving the RTC symbol and producing phase.
Verification after a fix
Keep two tests: one that intentionally produces “the server requires an explicit Content-Length body framing it received”, and one that applies the narrow correction; for this HRESULT, check the callback sequence, 0x80EF019B, final session/profile state, and absence of leaked listeners, dialogs, streams, or registrations.
Technical references
- Microsoft RTC return constants — authoritative context for the boundary.
- SIP response semantics — definitions relevant when reproducing it.
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