Non-interactive-cSharp login sample doesn't work in Linux+Mono

[Letrix]

Hello.

I am trying to use code from Non-interactive-cSharp login sample:
https://github.com/betfair/API-NG-sa...ractive-cSharp

In Windows this code works well. But when I try to run it in Linux using MonoDevelop I get:

System.ArgumentException
(Only 'http' and 'https' schemes are allowed.
Parameter name: requestUri)
for this line:

var result = client.PostAsync("/api/certlogin", content).Result;

Does someone know what is a problem here?
I also attached a screenshot:

1.jpg