Troubleshoot incoming IllyVoIP calls on a locked Android phone

First check whether the call reaches the intended IllyVoIP destination while the app is open. Then compare the same route with the phone locked. This separates account or routing problems from Android’s background and call-screen behavior.

1. Check the receiving destination

1. Sign in to the IllyVoIP mobile app with the intended account.
2. Open the dialer settings and check the selected SIP line and connection status. If a connection error is shown, resolve it before testing locked-screen behavior.
3. In the Portal, verify that the incoming number is active and its saved destination leads to that line or the intended queue or call flow. A number routed elsewhere will not ring this app simply because you are signed in.
4. If the route uses a queue or agent, check the relevant membership and availability. Do not change a working routing arrangement merely to test a phone setting.

The mobile app’s connection controls include a reconnect action when changes are allowed. Use it outside an active call if the connection needs refreshing. Do not reset credentials or weaken encryption as a generic incoming-call fix.

2. Identify what actually fails

Arrange one authorized incoming test while the app is open, then another with the app normally in the background and the phone locked. Record the times and resulting public call references from Call Reports. Ordinary call charges can apply. Avoid repeatedly force-closing the app between tests, which changes the condition you are investigating.

• No call in either state: investigate the saved destination, selected line and connection first.
• Call appears in the foreground but not when locked: inspect Android call-screen and notification permissions.
• Call appears but is silent: check alert settings, ringing volume and Do Not Disturb.
• Call can be answered but has no audio: investigate microphone access and the audio route; that is a different problem from missing ringing.

3. Review the lock-screen call warning

On supported Android versions, IllyVoIP can show Lock-screen calls are disabled with an Open settings action when the system denies full-screen call access. Follow that action and review the Android permission for this app, then return to IllyVoIP. Android 14 and later place additional controls on full-screen call notifications; the exact settings screen depends on the device.

The absence of that warning is not an end-to-end incoming-call test. It does not prove the number route, network or background notification delivery is working. Check the actual call after returning from settings.

4. Check Android alert and background settings

In Android Settings, find IllyVoIP under app notifications. Allow the call-related notifications you want and review whether they can alert on the lock screen. Android distinguishes silent and alerting notifications, and manufacturers arrange these controls differently. You can keep sensitive notification content hidden while reviewing whether call alerts are allowed.

Check Do Not Disturb and ringing volume if the screen appears without sound. If your device restricts background activity for IllyVoIP, review that app-specific battery or background setting using the manufacturer’s guidance. Do not assume one universal battery menu or disable all phone protections. Change one relevant setting at a time so you can tell what affected the result.

5. Repeat the same incoming route

Return to the app, confirm the selected line and connection, then repeat the locked-screen test. If useful, compare a trusted Wi-Fi connection with mobile data without changing the account or incoming destination. A result that follows one network is useful evidence; it is not a reason to permanently disable security software without investigation.

What to send Support

Provide your phone model, Android version, IllyVoIP app version, selected line, network type, test time and public call reference. Explain whether foreground ringing works, whether a call screen appeared and whether it was silent. Include a sanitized screenshot of any actual permission warning. Do not send your password, API key or an unredacted customer call list.

Related guides

• How to Read and Understand Your VoIP Call Reports (CDR)

Reference

Current instructions and technical reference: Android notification settings, Android full-screen call permissions.

Reviewed 12 October 2026 against the current IllyVoIP controls, implementation and applicable references. Available options depend on account permissions and service state.