Fix IronPdfEngine Docker Connection Failures on macOS ARM

Updated:June 9, 2026

When connecting a .NET application to IronPdfEngine via Docker on a macOS ARM device (Apple Silicon), the application throws:

Unhandled exception. System.IO.FileNotFoundException: Error loading native library.
Not found in any of the possible locations

IronPdfConnectionType.Docker uses an older gRPC implementation that does not support ARM architecture. On macOS ARM (Apple Silicon), the .NET client cannot load the required native gRPC binary, even when the Docker image is forced to run as --platform linux/amd64. Windows and Linux x64 platforms are not affected.

Solution

Replace IronPdfConnectionType.Docker with IronPdfConnectionType.RemoteServer in the connection configuration. RemoteServer uses a newer gRPC implementation that is ARM-compatible:

using IronPdf;

var config = new IronPdfConnectionConfiguration
{
    ConnectionType = IronPdfConnectionType.RemoteServer,
    Host = "http://127.0.0.1",
    Port = 33350
};

IronPdf.Installation.ConnectToIronPdfHost(config);

IronPdf.License.LicenseKey = Environment.GetEnvironmentVariable("IRONPDF_LICENSE_KEY");

var renderer = new ChromePdfRenderer();
var pdf = await renderer.RenderHtmlAsPdfAsync("<h1>Hello from IronPdfEngine</h1>");
pdf.SaveAs("output.pdf");

using IronPdf;

var config = new IronPdfConnectionConfiguration
{
    ConnectionType = IronPdfConnectionType.RemoteServer,
    Host = "http://127.0.0.1",
    Port = 33350
};

IronPdf.Installation.ConnectToIronPdfHost(config);

IronPdf.License.LicenseKey = Environment.GetEnvironmentVariable("IRONPDF_LICENSE_KEY");

var renderer = new ChromePdfRenderer();
var pdf = await renderer.RenderHtmlAsPdfAsync("<h1>Hello from IronPdfEngine</h1>");
pdf.SaveAs("output.pdf");

Imports IronPdf

Dim config As New IronPdfConnectionConfiguration With {
    .ConnectionType = IronPdfConnectionType.RemoteServer,
    .Host = "http://127.0.0.1",
    .Port = 33350
}

IronPdf.Installation.ConnectToIronPdfHost(config)

IronPdf.License.LicenseKey = Environment.GetEnvironmentVariable("IRONPDF_LICENSE_KEY")

Dim renderer As New ChromePdfRenderer()
Dim pdf = Await renderer.RenderHtmlAsPdfAsync("<h1>Hello from IronPdfEngine</h1>")
pdf.SaveAs("output.pdf")

$vbLabelText $csharpLabel

Requirements:

The IronPdfEngine Docker container must be running and reachable at the specified host and port before calling ConnectToIronPdfHost.
Use http://, not https://; using https:// without a valid SSL certificate causes frame corruption errors in the gRPC channel.

Curtis Chau

Chat with engineering team now

Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.

...

Ready to Get Started?

Nuget Downloads 19,345,590 | Version: 2026.6 just released