title: ASP.NET Core | gRPC "Error starting gRPC call: No connection could be made because the target machine actively refused it."
body: <p>I have a local gRPC client and a remote gRPC server. Local gRPC client is running on IIS. Remote gRPC server runs on Kestrel inside Ubuntu OS. When I'm trying to make a gRPC call from client to server I'm getting <strong>RpcException</strong> with the following message <code>"Error starting gRPC call: No connection could be made because the target machine actively refused it."</code>.</p>
  
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  <ul>
  <li>The firewall on the gRPC server machine is disabled.</li>
  <li>I have successfully intercepted incoming network packages on gRPC server with <strong>tcpdump</strong> and they seem ok. That means packages are reaching server machine and they are blocked by the application.</li>
  <li>I can access index page of gRPC server from gRPC client machine using browser.</li>
  <li>gRPC server Kestrel uses a self-signed SSL certificate.</li>
  </ul>