Send PDF File Stream always stuck in ASP.NET Core Web API

Question

I only want to generate .PDF and send it to consumer, I using ASP.NET Core 8 and docker linux, for PDF generator, I use PdfSharpCore.

This is my code:

[HttpGet("generatepdf")]
public async Task<IActionResult> GeneratePdf()
{
    // Membuat dokumen PDF baru
    var document = new PdfSharp.Pdf.PdfDocument();
    var page = document.AddPage();
    var graphics = XGraphics.FromPdfPage(page);
    var font = new XFont("Arial", 20, XFontStyleEx.Regular);

    // Menambahkan teks ke PDF
    graphics.DrawString("Hello, World!", font, XBrushes.Black, new XRect(0, 0, page.Width, page.Height), XStringFormats.Center);

    // Menyimpan PDF ke MemoryStream
    var stream = new MemoryStream();
    document.Save(stream, false);

    // Mengatur posisi stream ke awal
    stream.Position = 0;

    // Mengembalikan file PDF sebagai response dengan MIME type application/pdf
    return File(stream, "application/pdf", "GeneratedPdf.pdf");
}

I tried debug it using docker linux, and this happen

I already try breakpoint, and code always executes

return File(stream ...)

but I always get stuck with infinite loading.

If I use standard debug or dotnet run, it runs well.

Why does this happen and how to solve this?

Thanks