Why can't I send an audio stream from JavaScript via SignalR to a .NET Hub?

Question

I’m trying to send an audio stream captured in JavaScript from a browser tab to a .NET SignalR Hub. My goal is to stream audio in chunks/realTime to the server and broadcast it to all connected clients.

Here’s the setup:

SignalR Hub: I have a Hub named /SoundHub with the following method:

   public class SoundHub : Hub
    {
        public async Task SendAudioChunk(byte[] audioChunk)
        {
            await Clients.All.SendAsync("ReceiveAudio", audioChunk);
        }
    }

JavaScript Client: I’m capturing the system audio using navigator.mediaDevices.getDisplayMedia and sending audio chunks through SignalR. Here’s the JavaScript code:

window.startScreenSharing = async function () {
    try {
        const connection = new signalR.HubConnectionBuilder()
            .withUrl("/soundHub")
            .withAutomaticReconnect()
            .build();

        await connection.start();
        console.log("SignalR connection established.");

        const stream = await navigator.mediaDevices.getDisplayMedia({
            video: true,
            audio: true
        });

        const audioContext = new AudioContext();
        const audioSource = audioContext.createMediaStreamSource(stream);
        const processor = audioContext.createScriptProcessor(2048, 1, 1);

        audioSource.connect(processor);
        processor.connect(audioContext.destination);

        processor.onaudioprocess = async (event) => {
            const inputBuffer = event.inputBuffer.getChannelData(0);
            const intBuffer = new Int16Array(inputBuffer.length);
            for (let i = 0; i < inputBuffer.length; i++) {
                intBuffer[i] = Math.max(-32768, Math.min(32767, inputBuffer[i] * 32767));
            }
            const audioChunk = new Uint8Array(intBuffer.buffer);

            try {
                if (connection.state === signalR.HubConnectionState.Connected) {
                    await connection.invoke("SendAudioChunk", audioChunk);
                    console.log(`Audio chunk sent: ${audioChunk.length} bytes`);
                } else {
                    console.warn("SignalR connection is not in 'Connected' state.");
                }
            } catch (err) {
                console.error("Error sending audio chunk:", err);
            }
        };
    } catch (err) {
        console.error("Error setting up screen sharing and audio streaming:", err);
    }
};

Issue: If I change the Hub method to accept string instead of byte[] and send text data, it works fine. However, when I send audio chunks (Uint8Array), the method in the Hub is never triggered. I’ve added logging inside the method, but it seems the method is not even reached.

Troubleshooting: I verified that the JavaScript is capturing the audio correctly and sending the chunks. The SignalR connection is established, and the state is Connected when invoking SendAudioChunk.

No exceptions are thrown, but I receive an error in the browser console:

Error sending audio chunk: Error: Failed to invoke 'SendAudioChunk' due to an error on the server.

Question: Is there something wrong with the way I’m formatting the audio data (Uint8Array -> byte[])? Do I need to preprocess the audio differently before sending it? Why does sending text work, but sending audio chunks does not?

Additional Info: SignalR is working correctly with text data. I’m using Blazor Web App and the latest SignalR client.