GRPC Init throws "IOException: Failed to bind port " when running from .netcore app

Question

I have a .net core app which spins up a grpc server. I was able to run it locally without a problem until I had Windows updates today. After Windows applied latest updates, I tried to run my .net core app, but I keep getting the following error.

System.IO.IOException: Failed to bind port "127.0.0.1:50001" at Grpc.Core.Server.CheckPortsBoundSuccessfully()

I went to firewall and opened access to the port that grpc has problem accessing. It did not help. Anybody had this issue?

Answer 1

I wasted 2 days on this and finally got the answer. Windows update caused certain valid to use ports to be excluded and as a result I couldn't run any app that listens on those excluded ports.

Here is a link to Microsoft article. Windows update blocking previously valid ports