C# kestrel https working on windows but not on mac

Question

I have the following code:

var host = new WebHostBuilder()
   .UseKestrel()
   .UseUrls("https://*:" + port)
   .Configure(Configure)
   .Build();

which works wonderfully on windows - I can access it with https://127.0.0.1:1111 and it works fine. When I try it on a mac - it runs, but when I try and connect to it, it immediately just goes "connection closed"

I googled and found that in usekestrel, you should be able to add

   .UseKestrel( options => options.UseHttps...

which is documented here:

however when I try it, I'm only finding .UseSystemd as an option - no .useHttps - even though I'm referencing Microsoft.AspNetCore.Server.Kestrel.Https.

What am I doing wrong? Why does it behave differently on mac vs windows, and how do I fix it so that it also works on the mac?

Answer 1

so for anyone who runs across this - I found I guess an answer: you need to run in the terminal:

dotnet dev-certs https

which then asks you to run a really bizarre command:

sudo security set-key-partition-list -D localhost ...

which magically fixes things.