What does HRESULT 0x8004003C (TAPI_E_INVALIDTERMINALCLASS) mean?

TAPI_E_INVALIDTERMINALCLASS

The terminal class does not match the provider contract

TAPI_E_INVALIDTERMINALCLASS (0x8004003C) means the class identifier/name supplied when selecting or creating a terminal is not recognized for the current provider/media path.

Evidence to capture

Record requested terminal class, provider, address/stream media type, enumerated terminal classes, and any string/GUID mapping performed by the caller.

Focused correction

Select a terminal class advertised for that provider and media type. If an object of the right class is later invalid or busy, diagnose those separate terminal results.

Technical references

• Microsoft: TAPI_E constants.
• Microsoft: ITTerminal.
• Microsoft: TAPI 3.1 Reference.
• Microsoft: Telephony API interfaces.