due to Jenkins API changes, authentification doesn't work anymore with only crumb; should add SetCookie in addition to Crumb

[VirginiaNutu]

I solved the problem in the code by adding a member in IJenkinsContext CookieContainer setCookieHeader {get;}
Modified JenkinsClient

public void UpdateSecurityCrumb()
{
try {
this.setCookieHeader = null;
var cmd = new CrumbGetCommand(this);
cmd.Run();
Crumb = cmd.Result;
this.setCookieHeader = cmd.setCookieHeader;

        }
        catch (Exception error) {
            throw new JenkinsNetException("Failed to retrieve crumb!", error);
        }
    }

and all other classes till JenkinsHttpCommand where I set

request.CookieContainer = setCookieHeader;