Oauth step is returning 500 internal server error

Question

Hi,

I am new to UCWA, and I am trying to create online meeting using UCWA 2.0. I have identified the url by using auto discovery and also found the oauth URL. when I try to create the oauth token request, I am getting 500 internal server error. please let me know if I am missing any thing here. 

Below is the java script function 

$http({
    url: "https://lyncadd.company.com/WebTicket/oauthtoken",
    dataType: 'json',
    method: 'POST',
    data: 'grant_type=password&username=username @domain.com&password=somepwd',
}).then(function (response) {
    console.log(response);
}).catch(function (response) {
    console.log(response);    
});