diff --git a/CHANGES.md b/CHANGES.md
index 0e2d231e26..fe88aed5ab 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -22,6 +22,7 @@ Improvements 🙌:
 Bugfix 🐛:
  - Fixed ringtone handling (#2100 & #2246)
  - Messages encrypted with no way to decrypt after SDK update from 0.18 to 1.0.0 (#2252)
+ - Incoming call continues to ring if call is answered on another device (#1921)
  - Search Result | scroll jumps after pagination (#2238)
 
 Translations 🗣:
diff --git a/vector/src/main/java/im/vector/app/VectorApplication.kt b/vector/src/main/java/im/vector/app/VectorApplication.kt
index 4f89763cda..5be313d719 100644
--- a/vector/src/main/java/im/vector/app/VectorApplication.kt
+++ b/vector/src/main/java/im/vector/app/VectorApplication.kt
@@ -42,6 +42,7 @@ import im.vector.app.core.di.HasVectorInjector
 import im.vector.app.core.di.VectorComponent
 import im.vector.app.core.extensions.configureAndStart
 import im.vector.app.core.rx.RxConfig
+import im.vector.app.features.call.WebRtcPeerConnectionManager
 import im.vector.app.features.configuration.VectorConfiguration
 import im.vector.app.features.disclaimer.doNotShowDisclaimerDialog
 import im.vector.app.features.lifecycle.VectorActivityLifecycleCallbacks
@@ -89,6 +90,7 @@ class VectorApplication :
     @Inject lateinit var rxConfig: RxConfig
     @Inject lateinit var popupAlertManager: PopupAlertManager
     @Inject lateinit var pinLocker: PinLocker
+    @Inject lateinit var webRtcPeerConnectionManager: WebRtcPeerConnectionManager
 
     lateinit var vectorComponent: VectorComponent
 
@@ -173,6 +175,7 @@ class VectorApplication :
         })
         ProcessLifecycleOwner.get().lifecycle.addObserver(appStateHandler)
         ProcessLifecycleOwner.get().lifecycle.addObserver(pinLocker)
+        ProcessLifecycleOwner.get().lifecycle.addObserver(webRtcPeerConnectionManager)
         // This should be done as early as possible
         // initKnownEmojiHashSet(appContext)
 
diff --git a/vector/src/main/java/im/vector/app/features/call/VectorCallViewModel.kt b/vector/src/main/java/im/vector/app/features/call/VectorCallViewModel.kt
index edb75441c8..445f40e5b1 100644
--- a/vector/src/main/java/im/vector/app/features/call/VectorCallViewModel.kt
+++ b/vector/src/main/java/im/vector/app/features/call/VectorCallViewModel.kt
@@ -88,6 +88,11 @@ class VectorCallViewModel @AssistedInject constructor(
 
     private val currentCallListener = object : WebRtcPeerConnectionManager.CurrentCallListener {
         override fun onCurrentCallChange(call: MxCall?) {
+            // we need to check the state
+            if (call == null) {
+                // we should dismiss, e.g handled by other session?
+                _viewEvents.post(VectorCallViewEvents.DismissNoCall)
+            }
         }
 
         override fun onCaptureStateChanged() {
diff --git a/vector/src/main/java/im/vector/app/features/call/WebRtcPeerConnectionManager.kt b/vector/src/main/java/im/vector/app/features/call/WebRtcPeerConnectionManager.kt
index c70b52b09b..86b38c1158 100644
--- a/vector/src/main/java/im/vector/app/features/call/WebRtcPeerConnectionManager.kt
+++ b/vector/src/main/java/im/vector/app/features/call/WebRtcPeerConnectionManager.kt
@@ -19,10 +19,14 @@ package im.vector.app.features.call
 import android.content.Context
 import android.hardware.camera2.CameraManager
 import androidx.core.content.getSystemService
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleObserver
+import androidx.lifecycle.OnLifecycleEvent
 import im.vector.app.ActiveSessionDataSource
 import im.vector.app.core.services.BluetoothHeadsetReceiver
 import im.vector.app.core.services.CallService
 import im.vector.app.core.services.WiredHeadsetStateReceiver
+import im.vector.app.push.fcm.FcmHelper
 import io.reactivex.disposables.Disposable
 import io.reactivex.subjects.PublishSubject
 import io.reactivex.subjects.ReplaySubject
@@ -72,7 +76,7 @@ import javax.inject.Singleton
 class WebRtcPeerConnectionManager @Inject constructor(
         private val context: Context,
         private val activeSessionDataSource: ActiveSessionDataSource
-) : CallsListener {
+) : CallsListener, LifecycleObserver {
 
     private val currentSession: Session?
         get() = activeSessionDataSource.currentValue?.orNull()
@@ -170,6 +174,8 @@ class WebRtcPeerConnectionManager @Inject constructor(
 
     private var currentCaptureMode: CaptureFormat = CaptureFormat.HD
 
+    private var isInBackground: Boolean = true
+
     var capturerIsInError = false
         set(value) {
             field = value
@@ -201,6 +207,16 @@ class WebRtcPeerConnectionManager @Inject constructor(
         }
     }
 
+    @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
+    fun entersForeground() {
+        isInBackground = false
+    }
+
+    @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
+    fun entersBackground() {
+        isInBackground = true
+    }
+
     var currentCall: CallContext? = null
         set(value) {
             field = value
@@ -702,6 +718,18 @@ class WebRtcPeerConnectionManager @Inject constructor(
         )
 
         callContext.offerSdp = callInviteContent.offer
+
+        // If this is received while in background, the app will not sync,
+        // and thus won't be able to received events. For example if the call is
+        // accepted on an other session this device will continue ringing
+        if (isInBackground) {
+            if (FcmHelper.isPushSupported()) {
+                // only for push version as fdroid version is already doing it?
+                currentSession?.startAutomaticBackgroundSync(30, 0)
+            } else {
+                // Maybe increase sync freq? but how to set back to default values?
+            }
+        }
     }
 
     private fun createAnswer() {
@@ -849,6 +877,16 @@ class WebRtcPeerConnectionManager @Inject constructor(
         Timber.v("## VOIP onCallManagedByOtherSession: $callId")
         currentCall = null
         CallService.onNoActiveCall(context)
+
+        // did we start background sync? so we should stop it
+        if (isInBackground) {
+            if (FcmHelper.isPushSupported()) {
+                currentSession?.stopAnyBackgroundSync()
+            } else {
+                // for fdroid we should not stop, it should continue syncing
+                // maybe we should restore default timeout/delay though?
+            }
+        }
     }
 
     private inner class StreamObserver(val callContext: CallContext) : PeerConnection.Observer {