I see that the first lines in code blocks are not visible, posting it here again: public func provider(_ provider: CXProvider, perform action: CXAnswerCallAction) { guard let call = self.callManager?.callWithUUID(uuid: action.callUUID) else{ action.fail() return } call.data.isAccepted = true self.answerCall = call self.callManager?.updateCall(call) sendEvent(SwiftCallKeepPlugin.ACTION_CALL_ACCEPT, call.data.toJSON()) DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(1200)) { self.configureAudioSession() } action.fulfill() } public func waitForConnection(uuid: UUID, action: CXAnswerCallAction) { if(self.awaitedConnection.uuid != uuid) { action.fail() } else if(self.awaitedConnection.isConnected) { DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(1200)) { self.configureAudioSession() } action.fulfill() } else { DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(1000)) { self.waitForConnection(uuid: uuid, action: action) } } } public func provider(_ provider: CXProvider, perform action: CXAnswerCallAction) { guard let call = self.callManager?.callWithUUID(uuid: action.callUUID) else{ action.fail() return } call.data.isAccepted = true self.answerCall = call self.callManager?.updateCall(call) self.awaitedConnection.uuid = action.callUUID self.awaitedConnection.isConnected = false sendEvent(wiftCallKeepPlugin.ACTION_CALL_ACCEPT, call.data.toJSON()) waitForConnection(uuid: action.callUUID, action: action) } func configureAudioSession(){ let session = AVAudioSession.sharedInstance() do{ try session.setCategory(AVAudioSession.Category.playAndRecord, options: AVAudioSession.CategoryOptions.allowBluetooth) try session.setMode(self.getAudioSessionMode(data?.audioSessionMode ?? "voiceChat")) try session.setActive(data?.audioSessionActive ?? true) try session.setPreferredSampleRate(data?.audioSessionPreferredSampleRate ?? 44100.0) try session.setPreferredIOBufferDuration(data?.audioSessionPreferredIOBufferDuration ?? 0.005) }catch{ print(error) } }