How to access files in outside of bin folder in ASP.NET Core?

I am developing a web app in ASP.net Core MVC and am trying to access a TempFile in a folder called TempFile within my project.

MyWebAPP:.
├───TempFiles
     ├─── file.wav

However I cannot access that file, even tho it exists, through JavaScript, like this:

const connection = new signalR.HubConnectionBuilder().withUrl("/SandboxHub").build();

// Start the SignalR connection
connection.start().catch(err => console.error(err));

// Handle textbox change event
$("#sentence-input").on("input", async function () {
    // Get the sentence value
    const sentence = $(this).val();

    // Send the sentence to the Hub
    await connection.invoke("TransformIntoTTS", sentence);

    connection.on("ReceiveFile", function (fileUrl) {
        const relativeFilePath = fileUrl.replace("/LearningWithAI-WebLayer", "");


        // Apply the file URL to the source of the audio controller
        $("#audio-player").attr("src", "../" + relativeFilePath);

    });
});

I suggest you could try to create the folder inside the wwwroot folder instead of using the project's default web root folder, since only wwwroot folder inside the asp.net core could be accessed by the client.

If you want to serve files outside of web root, you should try to use below codes:

using Microsoft.Extensions.FileProviders;

app.UseStaticFiles(new StaticFileOptions
{
    FileProvider = new PhysicalFileProvider(
           Path.Combine(builder.Environment.ContentRootPath, "TempFiles")),
    RequestPath = "/TempFiles"
});

More details about how static files works inside asp.net core, you could refer to this article.