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TAPI_E_NOREQUESTRECIPIENT
No program is available to handle the request
TAPI_E_NOREQUESTRECIPIENT is HRESULT 2147745842 (0X80040032) from Tapi3err.h. AllStat describes it as “No program is available to handle the request.” The result normally appears while submitting a request for which no registered application can act as recipient. Its useful interpretation is precise: the Assisted Telephony request recipient is not valid for the exact provider, object, method, or lifecycle state that consumed it.
Owning component and lifecycle
- This result belongs to TAPI 3 address, call-control, phone, terminal, media-provider, request, or call-center processing.
- Associate this result with one concrete native method among ITTAPI, ITAddress, ITBasicCallControl, ITCallInfo, ITStream, ITTerminal, ITPhone, provider events, and Assisted Telephony.
- Before releasing objects after this result, retain provider identity, object generation, current state, requested transition, and the event sequence surrounding submitting a request for which no registered application can act as recipient.
When the application constructed the Assisted Telephony request recipient, it usually calls for caller-side validation. When enumeration or an event supplied it, it more often points to stale lifetime, provider replacement, device removal, configuration drift, or cross-session reuse. The ownership distinction for this HRESULT prevents a broad repair from masking the real defect.
Plausible explanations
- It can occur when the caller supplies a malformed, unsupported, stale, or out-of-scope Assisted Telephony request recipient.
- It can also indicate that the Assisted Telephony request recipient belonged to another address, call, device, provider generation, user session, or COM object.
- An asynchronous event can produce it when removal, disconnect, cancellation, reinitialization, or a state transition occurs after validation.
- A wrapper can trigger it by converting an enumeration, identifier, duration, structure size, encoding, or ownership rule incorrectly.
Choose among those branches only after comparing the failed Assisted Telephony request recipient with live capabilities or objects obtained from the same provider generation. A well-formed value can still be invalid because its scope, owner, state, or lifetime no longer matches the operation.
What to log before cleanup
- Record it, 0X80040032, the native method, operation ID, elapsed time, process and thread IDs, application build, architecture, and COM apartment.
- capture request mode, media type, destination, registered applications, priority, user session, and executable availability.
- Keep provider version, address/call/phone/terminal identities, current state, requested state, object generation, and the first lower-level error that preceded it.
- Redact telephone numbers, credentials, recordings, user-user data, and directory attributes from it telemetry while retaining lengths, types, hashes, ranges, capability flags, and opaque correlation identifiers.
A useful incident can answer whether the Assisted Telephony request recipient came from configuration, enumeration, user input, cached state, or a provider callback. The result record should also show whether the operation succeeds with a newly enumerated object or freshly validated value.
Reproduction and diagnosis
- Capture it at the first native return and identify the exact method used for submitting a request for which no registered application can act as recipient.
- Validate the Assisted Telephony request recipient without silently correcting it; check type, size, range, encoding, identifier scope, ownership, and lifetime as applicable.
- Enumerate current provider capabilities or objects and compare them with the Assisted Telephony request recipient rejected by it.
- Reconstruct the event timeline before it to find removal, disconnect, cancellation, service restart, provider reinitialization, or another state transition.
- Reproduce it with one object and one operation, then vary only the suspected field or state while tracking partial output and side effects.
Handling the result
The evidence-based correction for this HRESULT is to install or register an appropriate recipient and verify it is eligible in the current user session. After it follows a provider, device, service, or configuration change, obtain a fresh object because an old interface or opaque identifier may remain invalid after recovery.
Practical example
For example, a web page requests a voice call on a kiosk where no call handler is registered; installing the softphone supplies a recipient The application should log the failed Assisted Telephony request recipient, provider and object generation, native method, and state-changing event, then verify recovery with a newly obtained object instead of reusing the instance that returned it.
Related-result boundary
TAPI_E_NOTREGISTERED concerns the current handler’s registration; it means no eligible program exists Keep that distinction when building dashboards and exception mappings for this HRESULT; otherwise input defects, lifecycle races, capacity limits, service outages, and final call outcomes collapse into one misleading category.
Long-term prevention
Operational repair for this HRESULT should target only the component identified by evidence: the Telephony service, service provider, COM server, device, configuration record, application package, or remote system. Copying arbitrary DLLs or broadly deleting registration data can create additional failures without correcting the original Assisted Telephony request recipient.
References
- Microsoft: TAPI_E constants — official Microsoft documentation used to interpret it.
- Microsoft: TAPI 3.1 Reference
- Microsoft: Telephony API interfaces
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