diff --git a/src/api/ngcp-call.js b/src/api/ngcp-call.js
index 959ea271..6cb108ff 100644
--- a/src/api/ngcp-call.js
+++ b/src/api/ngcp-call.js
@@ -134,18 +134,25 @@ export function callRegister ({ instanceId }) {
         delegateEvent('registrationFailed')
         $userAgent.on('newRTCSession', (event) => {
             if (event.originator === 'remote') {
-                $incomingRtcSession = event.session
-                $incomingRtcSession.on('peerconnection', () => {
-                    $incomingRtcSession.connection.ontrack = handleRemoteMediaStream
-                })
-                $incomingRtcSession.on('failed', (failedEvent) => {
-                    callEvent.emit('incomingFailed', failedEvent)
-                })
-                $incomingRtcSession.on('ended', (failedEvent) => {
-                    callEvent.emit('incomingEnded', failedEvent)
-                    $incomingRtcSession = null
-                })
-                callEvent.emit('incoming', $incomingRtcSession)
+                if ($incomingRtcSession || $outgoingRtcSession) {
+                    event.session.terminate({
+                        status_code: 486,
+                        reason_phrase: 'Busy'
+                    })
+                } else {
+                    $incomingRtcSession = event.session
+                    $incomingRtcSession.on('peerconnection', () => {
+                        $incomingRtcSession.connection.ontrack = handleRemoteMediaStream
+                    })
+                    $incomingRtcSession.on('failed', (failedEvent) => {
+                        callEvent.emit('incomingFailed', failedEvent)
+                    })
+                    $incomingRtcSession.on('ended', (failedEvent) => {
+                        callEvent.emit('incomingEnded', failedEvent)
+                        $incomingRtcSession = null
+                    })
+                    callEvent.emit('incoming', $incomingRtcSession)
+                }
             }
         })
         $userAgent.start()
diff --git a/src/store/call/actions.js b/src/store/call/actions.js
index d06a2fac..c485c59c 100644
--- a/src/store/call/actions.js
+++ b/src/store/call/actions.js
@@ -77,12 +77,14 @@ export default {
             context.commit('hangUpCall')
         } else if (options.cause && !errorVisibilityTimer) {
             context.commit('endCall', options.cause)
-            errorVisibilityTimer = setTimeout(() => {
-                if (context.state.callState === 'ended') {
-                    context.commit('hangUpCall')
-                }
-                errorVisibilityTimer = null
-            }, errorVisibilityTimeout)
+            if (options.cause !== 'Busy') {
+                errorVisibilityTimer = setTimeout(() => {
+                    if (context.state.callState === 'ended') {
+                        context.commit('hangUpCall')
+                    }
+                    errorVisibilityTimer = null
+                }, errorVisibilityTimeout)
+            }
         }
     },
     sendDTMF (context, tone) {