ICall.PlayPromptAsync returns unknown error with HResult 0x80131500

I'm trying to play prompt after call connects with the following codes:

    private async void CallOnUpdated(ICall sender, ResourceEventArgs<Call> e)
    {
        if ((e.OldResource.State != e.NewResource.State) && (e.NewResource.State == CallState.Established))
        {
            var prompts = new List<MediaPrompt>()
            {
                new MediaPrompt
                {
                    MediaInfo = new MediaInfo
                    {
                        Uri = "https://url.mydomain.com/prompt.wav",
                        ResourceId = Guid.NewGuid().ToString(),
                    }
                }
            };
            await this.Call.PlayPromptAsync(prompts).ConfigureAwait(false);
       }
    }

But I get exception as follow when I call ICall.PlayPromptAsync. Anyone experiences this?

Exception detail:
Microsoft.Graph.Communications.Core.Exceptions.ServiceException
HResult=0x80131500
Message=Code: UnknownError
Message: Unexpected exception returned from the service.
Status Code: InternalServerError
Scenario Id: 75dfa437-baf0-4272-b536-7cc78fe4d6d0
Inner error:
AdditionalData:
date: 2022-05-11T06:46:00
request-id: b39dff5e-d0f3-4d53-9ee4-fd81884f2d7e
client-request-id: 40f6594e-bb19-45a5-a158-fe3d8582ed23

Source=Microsoft.Graph.Communications.Client
StackTrace:
at Microsoft.Graph.Communications.Client.Transport.GraphClientWrapper.d__121.MoveNext() at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.Graph.Communications.Client.Transport.GraphClientWrapper.<SendAsync>d__112.MoveNext()
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.Graph.Communications.Client.GraphClientExtensions.d__01.MoveNext() at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.Graph.Communications.Resources.InternalResourceExtensions.<>c__DisplayClass2_01.<b__0>d.MoveNext()
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.Graph.Communications.Client.OperationManager.d__101.MoveNext() at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.Graph.Communications.Calls.StatefulCall.<PlayPromptAsync>d__21.MoveNext() at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.ConfiguredTaskAwaitable1.ConfiguredTaskAwaiter.GetResult()
at RecordingBot.Services.Bot.CallHandler.d__16.MoveNext() in C:\Users\Administrator\source\repos\microsoft-graph-comms-samples\Samples\V1.0Samples\AksSamples\teams-recording-bot\src\RecordingBot.Services\Bot\CallHandler.cs:line 230

This exception was originally thrown at this call stack:
[External Code]

Inner Exception 1:
ServiceException: Code: UnknownError
Message: Unexpected exception returned from the service.
Status Code: InternalServerError
Inner error:
AdditionalData:
date: 2022-05-11T06:46:00
request-id: b39dff5e-d0f3-4d53-9ee4-fd81884f2d7e
client-request-id: 40f6594e-bb19-45a5-a158-fe3d8582ed23

Start at Samples/V1.0Samples/AksSamples/teams-recording-bot/src/RecordingBot.Services/Bot/CallHandler.cs line 230, where Call.PlayPromptAsync is called after the call reaches Established. Reproduce the request using the shown MediaPrompt and MediaInfo values, then inspect the service response and related call or prompt APIs. Done means identifying the cause of the InternalServerError or documenting the required conditions for playback.