IronPdf on .NET 6+: Grpc.Core Build Errors or Proxy Ignored (Engine Connections)

Overview

IronPDF 2026.11.1 removes the deprecated Grpc.Core package from its .NET 6+ client and moves engine connections to the managed gRPC stack. Code that uses Grpc.Core types such as Channel, GrpcEnvironment or Grpc.Core.Logging no longer gets that package through IronPDF and fails to build, and Docker and LocalExecutable connections stop using proxy environment variables. Add a direct Grpc.Core reference, and connect to the engine directly.

error CS0234: The type or namespace name 'Channel' does not exist in the namespace 'Grpc.Core' (are you missing an assembly reference?)

error CS0234: The type or namespace name 'Logging' does not exist in the namespace 'Grpc.Core' (are you missing an assembly reference?)

error CS0246: The type or namespace name 'Channel' could not be found (are you missing a using directive or an assembly reference?)

Environment

OS: Any
Hosting: Applications that connect to IronPdfEngine (Docker, LocalExecutable, RemoteServer)
Language/Runtime: .NET 6 and later. .NET Framework and .NET Standard 2.0 projects still get Grpc.Core through IronPDF and are not affected.

Version Metadata

Version found: 2026.11.1
Version resolved: N/A

Cause

From 2026.11.1, IronPDF's .NET 6 and .NET 8 builds use Grpc.Net.Client instead of the deprecated Grpc.Core, so code that used Grpc.Core-only types (such as Channel, GrpcEnvironment or Grpc.Core.Logging) no longer gets them through IronPDF. The new stack also stops Docker and LocalExecutable connections from reading grpc_proxy, https_proxy or http_proxy, and RemoteServer connections from reading grpc_proxy.

Solution

Build errors CS0234, CS0246, CS0103 or CS1061 for Grpc.Core types on .NET 6+

Affected: Channel, ChannelOption, ChannelState, GrpcEnvironment, Grpc.Core.Logging and the ToListAsync / ForEachAsync extensions. ChannelBase, Metadata, ChannelCredentials and RpcException still build.

Recommended: Add a direct reference to Grpc.Core, and your existing code builds again:
```
dotnet add package Grpc.Core 
```

Alternatively, remove Grpc.Core.Logging code used only for debugging, or replace a custom channel with a built-in preset such as IronPdfConnectionConfiguration.Docker.

Engine traffic no longer goes through your proxy

This change is intended. Docker and LocalExecutable connections now go directly to the engine address, even when a proxy variable is set. Make sure the application can reach the engine host and port directly, for example by running the engine on the same host or Docker network:
```
Installation.ConnectToIronPdfHost(IronPdfConnectionConfiguration.Docker); 
```
RemoteServer connections still use https_proxy, http_proxy and the Windows system proxy. If you set the proxy only in grpc_proxy, move it to https_proxy or http_proxy. With WithCustomChannel, your own channel's proxy settings apply.

References

gRPC blog, "The future of gRPC in C# belongs to grpc-dotnet" (Grpc.Core deprecation): https://grpc.io/blog/grpc-csharp-future/
Grpc.Core on NuGet: https://www.nuget.org/packages/Grpc.Core
About IronPdfEngine: https://ironpdf.com/get-started/ironpdfengine/
Related: fixing gRPC connection errors with IronPDF in Azure containers: https://ironpdf.com/troubleshooting/azure-grpc-connection-errors/