API authentication issue

[Ramaswami]

Hi folks, 

i am writing a javascript code to get the access token from an API using grant_type = password but i am getting the below error : 

Results = {"reason":"Unknown grant_type"}

HTTP header 'WWW-Authenticate' used for proxy authentication not found.

script : 

var http = new HttpClientRequest("https://api.trustpilot.com/v1/oauth/oauth-business-users-for-applications/accesstoken")

var buffer = new MemoryBuffer()
buffer.fromString("hrIrJQO0rKQdWSf" + ':' + "AK4ceo", "iso-8859-1");
http.header["Content-Type"] = "application/x-www-form-urlencoded";
http.header["Authorization"] = "Basic " + buffer.toBase64();
http.header["grant_type"] = "password";
http.header["username"] = "abc.com;
http.header["password"] = "PaneL321!@";
http.body = "grant_type=password&username=abc.com&password=PanesddL321!@";
http.method = "GET"

http.execute()

var result = http.response.body.toString();
logInfo("Results = " + result)

[amritakedia_epsilon]

Make sure there is no firewall blocking 

[_Manoj_Kumar_ · Accepted solution]

Hello @Ramaswami 

First change the http.method to POST then

try removing these 3 headers from your request.

http.header["grant_type"] = "password";
http.header["username"] = "abc.com;
http.header["password"] = "PaneL321!@";

According to the official trust pilot documentation, It is only accepting the authorization header,content Type and the Form data.

Also, you can refer to this documentation for additional troubleshooting: https://developers.trustpilot.com/authentication

Let me know if that works.

Thanks,