Can't get the Audio Transcription to work in Unity C#

[chiddyBenno]

Hello dear openai-dotnet Community.
Im currently working on a OpenAI integration in my VR-Unity Project.
I was previously working with Azure SST & TTS and want to change it all to the OpenAI-API.

Even trying out the simple Example:
`public async Task Example02_SimpleTranscriptionAsync()
{
AudioClient client = new("whisper-1", Environment.GetEnvironmentVariable("OPENAI_API_KEY"));

    string audioFilePath = Path.Combine("Assets", "audio_houseplant_care.mp3");

    AudioTranscription transcription = await client.TranscribeAudioAsync(audioFilePath);

    Console.WriteLine($"{transcription.Text}");
}`

it will give me this error:

Error: boundary
UnityEngine.Debug:Log (object)
SpeechToTextManager/<Example02_SimpleTranscriptionAsync>d__14:MoveNext () (at Assets/02-KiChatGPT/SpeechToTextManager.cs:70)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start<SpeechToTextManager/<Example02_SimpleTranscriptionAsync>d__14> (SpeechToTextManager/<Example02_SimpleTranscriptionAsync>d__14&)
SpeechToTextManager:Example02_SimpleTranscriptionAsync ()
SpeechToTextManager:StartSpeechToText () (at Assets/02-KiChatGPT/SpeechToTextManager.cs:47)
NewOpenAIController:Start () (at Assets/02-KiChatGPT/NewOpenAIController.cs:57)

I would be very grateful if somebody could help me with it.
Greetings,
Benjamin