for a API Connection it is required to have a oauth Authentication. I think on the Server is not configured/installed. Because if i test this with a API Testtool i got this Message:
{
"errors": [{
"code": "2",
"status": "400",
"title": "The authorization grant type is not supported by the authorization server.",
"detail": "Check that all required parameters have been provided"
}]
}
I have already setup oAuth on ubuntu for my past clients. Will debug the current issues on your setup and make oAuth authentication work fine. Linux server admin here with 6+ years of experience.
Ping me and lets discuss further.
Thanks