Closed captions and live transcript in iOS Zoom SDK in Custom UI

I have integrated Zoom Video SDK for zoom meeting in iOS application. I have implemented Custom UI. everything is working fine. Now I need to implement closed captions and live transcription feature. I have implemented the code but the delegates are not getting called. Please help here.

Code -

 let liveTranscriptionHelper = ZoomVideoSDK.shareInstance()?.getLiveTranscriptionHelper()
 ZoomVideoSDK.shareInstance()?.delegate = self


func onLiveTranscriptionMsgReceived(_ messageInfo:       ZoomVideoSDKLiveTranscriptionMessageInfo?) {
    print("MessageInfoContent is :\(messageInfo?.messageContent ?? "")")

func onLiveTranscriptionStatus(_ status: ZoomVideoSDKLiveTranscriptionStatus) {
    print("Status of received transcript -\(status)")
func onLiveTranscriptionMsgError(_ spokenLanguage:     ZoomVideoSDKLiveTranscriptionLanguage?, transLanguage transcriptLanguage:      ZoomVideoSDKLiveTranscriptionLanguage?) {
    print("Error while receiving translation")

Only the second delegate is getting called i.e - onLiveTranscriptionStatus