Check the intended IllyVoIP line and incoming destination before changing iPhone settings. A call routed to another destination will not reach this app, while a call that appears silently needs a different investigation from one that never appears.
1. Confirm the account and selected line
- Open IllyVoIP and confirm that you are signed in to the intended account.
- Open the dialer settings and inspect the selected SIP line and connection state. Record any visible connection error.
- In the Portal, check the incoming number’s state and saved destination. If it uses a queue or call flow, verify that the route can reach the intended user and that the user is available as required.
- If a reconnect is needed, use the app’s connection control outside an active call. Recheck the state before testing again.
Do not rotate the account password or change routing at random. These changes affect other devices or integrations and can make an intermittent mobile issue harder to isolate.
2. Compare foreground and locked-screen calls
Arrange an authorized incoming call while the app is open. Note whether it appears, rings and can be answered. Then leave the app normally in the background, lock the iPhone and repeat the same incoming route. Keep the times and public call references; ordinary call charges can apply.
If neither attempt arrives, focus first on the incoming destination, line and connection. If only the locked-screen attempt fails, record that distinction for the mobile investigation. A missed-call report alone does not establish whether the failure was routing, alert presentation or user availability.
3. Check Focus and sound when calls are silent
Review the active Focus in iPhone Settings. A Focus can allow or silence selected people and apps, and schedules can enable it again later. Check the relevant allowances and any automatic schedule rather than assuming that turning it off once permanently changes your normal setup. Keep the privacy and interruption settings you need.
Check the phone’s silent/ringing state and volume when a call appears without sound. Review IllyVoIP’s notification settings if its alerts are disabled. Native incoming-call presentation and ordinary app notifications are not identical, so an enabled notification switch alone does not prove that an incoming VoIP call can reach the phone.
4. Separate call arrival from audio access
IllyVoIP integrates with iPhone’s native calling interface. If that interface appears and you can answer, the next question is whether both sides hear audio. Check the app’s microphone permission and selected audio output if the answered call is silent. Microphone access is relevant to your speech; it is not proof that a missing incoming call was caused by the microphone toggle.
If a headset or other audio device is connected, inspect the active output during a suitable test. Do not disconnect devices in the middle of another person’s call merely for troubleshooting.
5. Check connectivity without changing everything
Open the app again and confirm its current connection. If the problem is reproducible, compare trusted Wi-Fi and mobile data while keeping the same account, selected line and incoming route. Record which condition fails. Follow your organization’s network policy rather than broadly removing VPN, encryption or security settings.
Use the IllyVoIP app version supplied through your normal authorized distribution channel. Menu labels can vary by iOS or app version. Reinstalling should not be the first step: it can remove useful local state without showing why the incoming call failed.
Escalate with a reproducible example
- iPhone model, iOS version and IllyVoIP app version.
- Selected line and the incoming destination, supplied privately.
- Whether the app was open, normally backgrounded or the phone was locked.
- Whether the call screen appeared, whether it made a sound and whether answering worked.
- Network type, approximate UTC test time and public call reference.
- Any visible connection error and the relevant Focus state.
Support can use those facts to compare the actual call result with the mobile symptom. Do not send account credentials or claim that a notification setting has fixed the issue until the same incoming route succeeds in the state that previously failed.
Related guides
Reference
Current instructions and technical reference: Apple iPhone Focus settings, Apple native calling interface.
Reviewed 12 October 2026 against the current IllyVoIP controls, implementation and applicable references. Available options depend on account permissions and service state.