NuGet microsoft.cognitiveservices.speech produces 0kb files

I have been using this code for a month. My azure account is in good standing. However, when I run it now, it produces a 0kb file. The amount of text I am attempting to generate is around 700 words.

using Microsoft.CognitiveServices.Speech.Audio;using Microsoft.CognitiveServices.Speech;namespace TextToSpeech{    class Program    {        static async Task Main()        {            await SynthsizeAudioAsync();        }        static async Task SynthsizeAudioAsync()        {            var config = SpeechConfig.FromSubscription("***", "***");            config.SpeechSynthesisVoiceName = "en-US-ChristopherNeural";            AudioConfig audioConfig = AudioConfig.FromWavFileOutput("D:\\file.wav");            using var synthesizer = new SpeechSynthesizer(config, audioConfig);            await synthesizer.SpeakTextAsync("Hello!");        }    }}

There are no errors, but when it attempts to synthesize the speech it "crashes" and creates a 0kb file. I have tried generating an mp3 instead and it creats a 0kb mp3. I am not sure what to do from here. Thanks for looking into this.

I tried to change the api key, I have tried to change the voice. I have upgraded my azure account to basic plan. I have tried to add logging but it is actually running all the code. It thinks that it has finished but really the files are empty.