Using custom function with Desk API v1 and OAuth Connection -> Invalid oauth token

Using custom function with Desk API v1 and OAuth Connection -> Invalid oauth token

Hi,

since there's no comment module (as far as I can see) in Zoho Deluge Desk Integration I tried to 

1. 
Creating OAuth Connection for the needed scope of Zoho.Desk.Tickets.ALL 

2.
Writing this code in custom function (TicketID comes with argument):

comment = "test-comment";
commentMap = Map();
commentMap.put("content",comment);
commentMap.put("contentType","html");
commentMap.put("isPublic","false");
parameters = commentMap.toString();
stringURL = "https://desk.zoho.com/api/v1/tickets/" + TicketID + "/comments";
response = invokeurl
[
url : stringURL
type : POST
parameters : parameters
connection : "deskoauth"
];
info response;


As a result I get "invalid oauthtoken". Any help is appreciated.

Thanks.