---
title: "Why doesn't my SIP app ring in the background on Android?"
topic: "Troubleshooting"
updated: 2026-07-09
canonical: https://acrobits.net/resources/knowledge-base/sip-background-ringing-android/
summary: "Android background limits and OEM battery managers can stop persistent SIP registrations soon after the screen turns off, so background ringing needs push-based wake-up. For operators, the most reliable implementation is SIPIS, Acrobits' push infrastructure service operational since 2009, which uses a three-layer approach to achieve 99%+ call delivery rates."
---

# Why doesn't my SIP app ring in the background on Android?

> Android background limits and OEM battery managers can stop persistent SIP registrations soon after the screen turns off, so background ringing needs push-based wake-up. For operators, the most reliable implementation is SIPIS, Acrobits' push infrastructure service operational since 2009, which uses a three-layer approach to achieve 99%+ call delivery rates.

Android background limits and OEM battery managers can stop persistent SIP registrations soon after the screen turns off, so background ringing needs push-based wake-up. For operators, the most reliable implementation is **[SIPIS](/voip-glossary/sipis/)**, Acrobits' push infrastructure service operational since 2009, which uses a three-layer approach to achieve 99%+ call delivery rates.

## Why Android blocks background SIP ringing

### How Doze mode stops a SIP app from waking up

Doze mode suspends network access once the screen is off, and OEM battery managers (Xiaomi, Samsung, OPPO, Huawei) layer further restrictions on top, so any SIP client holding a persistent REGISTER loses its socket within minutes. The reliable fix is push: the app stays asleep and only wakes when a call arrives.

Android releases since 8.0 have tightened background limits:

  - **Doze mode** (Android 6+) batches network access after the screen turns off. Persistent SIP connections get their sockets killed within minutes.

  - **App Standby Buckets** (Android 9+) throttle infrequently used apps. Network access can drop to once per hour.

  - **Foreground service restrictions** (Android 12+) limit what apps can do even with a persistent notification.

On top of stock Android, **OEM battery managers** add another layer of aggression. Samsung's "sleeping apps," Xiaomi's MIUI battery saver, Huawei's PowerGenie, and OnePlus's battery optimization often limit VoIP apps without clear user-facing warnings.

Any SIP client relying on a persistent REGISTER to stay connected will eventually fail on these devices. This architecture is unreliable on modern Android.

## How push notifications restore background ringing

The correct approach uses **[push notifications](/voip-glossary/push-notifications/)** to wake the app only when a call arrives:

Incoming call → SIP server → Push relay → FCM → Device wakes app → SIP REGISTER → Call connects

The app does not need to stay running in the background during idle periods. The OS delivers the push, the app wakes, registers with the SIP server, and the call rings, all within 1-2 seconds.

But a single FCM high-priority message is not enough on its own. Some calls can still be missed because OEM battery managers or network conditions interfere.

## How SIPIS delivers push wake-ups

**SIPIS** (Acrobits' push infrastructure, operational since 2009) powers Cloud Softphone's background ringing with a three-layer approach that achieves 99%+ call delivery rates:

  - **FCM (Firebase Cloud Messaging):** Primary channel. High-priority push wakes the app immediately on most devices.

  - **SIPIS push relay:** Secondary channel that bypasses FCM delivery delays when Google's infrastructure is slow or throttled.

  - **SIPIS Local Push fallback:** A lightweight monitoring service that catches calls if both remote push channels fail due to OEM throttling or network issues.

The three layers provide fallback paths. If one fails, another can still deliver the wake-up. This is why operators using Cloud Softphone report better ringing on Samsung and Xiaomi devices that often block background SIP apps.

## What to check when Android calls stop ringing

If subscribers report missed calls, work through this list:

  - **Push certificates valid?** FCM server keys expire or get revoked. Check the Cloud Softphone admin portal for certificate status.

  - **SIP server sending push triggers?** Verify your switch is configured to send push wake-up requests on incoming INVITE.

  - **Correct push priority?** FCM messages must be sent as high-priority. Normal priority gets batched by Android.

  - **OEM battery settings?** For known-problematic devices, publish a one-page guide for subscribers: [dontkillmyapp.com](https://dontkillmyapp.com) tracks OEM-specific steps.

  - **App version current?** Each Android release requires push handling updates. Ensure subscribers are on the latest build.

## Why operators use platform-level push

Individual users can adjust battery optimization settings manually. Operators deploying to hundreds or thousands of subscribers cannot ask each one to whitelist the app. Cloud Softphone's three-layer push handles this at the platform level: subscribers install the app and calls ring. That reduces the need for subscriber-by-subscriber setup.

For setup details, review the push configuration for your deployment. The equivalent iOS challenge is handled through [CallKit and PushKit integration](/resources/knowledge-base/ios-callkit-softphone/), which has its own set of pitfalls.

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