Link crash

Build version: 1.7.1
Build date: 1981-01-01 01:01:02
Current date: 2021-09-24 09:07:23
Device: Xiaomi Redmi Note 9 Pro
OS version: Android 10 (SDK 29)

Stack trace:
java.lang.NullPointerException
    at java.util.concurrent.ConcurrentHashMap.putVal(ConcurrentHashMap.java:1019)
    at java.util.concurrent.ConcurrentHashMap.put(ConcurrentHashMap.java:1014)
    at com.civix.link.Libraries.JanusWithGoogle.meet.MeetingService.subscribe(MeetingService.java:119)
    at com.civix.link.Libraries.JanusWithGoogle.meet.MeetingClient.subscribe(MeetingClient.java:116)
    at com.civix.link.Screen.CallScreen.subscriberToUser(CallScreen.kt:1719)
    at com.civix.link.Screen.CallScreen$getMediaList$1.onSuccess(CallScreen.kt:1132)
    at com.civix.link.Network.ApiHelper$getData$1.onResponse(ApiHelper.kt:98)
    at com.androidnetworking.common.ANRequest.deliverSuccessResponse(ANRequest.java:727)
    at com.androidnetworking.common.ANRequest.access$6500(ANRequest.java:80)
    at com.androidnetworking.common.ANRequest$6.run(ANRequest.java:709)
    at android.os.Handler.handleCallback(Handler.java:883)
    at android.os.Handler.dispatchMessage(Handler.java:100)
    at android.os.Looper.loop(Looper.java:224)
    at android.app.ActivityThread.main(ActivityThread.java:7562)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)

User actions:
2021-09-24 09:07:14: ChatScreen created
2021-09-24 09:07:14: ChatScreen resumed
2021-09-24 09:07:17: ChatScreen paused
2021-09-24 09:07:17: ChatScreen resumed
2021-09-24 09:07:21: ChatScreen paused
2021-09-24 09:07:21: CallScreen created
2021-09-24 09:07:21: CallScreen resumed
2021-09-24 09:07:21: CallScreen paused
2021-09-24 09:07:21: CallScreen resumed