uber api ride request getting 401 unautherized error response - objective-c

Question

I am trying to build mac osx application For UBER.I have completed all steps of Aouth2. I am successfully getting access_token. I am also able to retrieve user profile and history but while I am trying to post "ride request", I am getting 401 unauthorized error response.please help.Thank you In advance.
My code is as below.
**
//POST /v1/requests
NSString *sandBoxURL=#"https://sandbox-api.uber.com/v1";
NSString *url = [NSString stringWithFormat:#"%#/requests", sandBoxURL];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:url]];
[request addValue:#"application/json; charset=utf-8" forHTTPHeaderField:#"Content-Type"];
[request addValue:[NSString stringWithFormat:#"Bearer %#", _accessToken] forHTTPHeaderField:#"Authorization"];
NSError *error = nil;
request.HTTPMethod = #"POST";
request.HTTPBody = [NSJSONSerialization dataWithJSONObject:params options:0 error:&error];
NSLog(#"Request for Product Request:%#",request);
[self performNetworkOperationWithRequest:request completionHandler:^(NSDictionary *requestDictionary, NSURLResponse *response, NSError *error)
{
NSLog(#"Response for Product Request:%#",response);
NSLog(#"Result:%#",requestDictionary);
NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
if (httpResponse.statusCode >= 200 && httpResponse.statusCode < 300)
{ //OK
UberRequest *requestResult = [[UberRequest alloc] initWithDictionary:requestDictionary];
// handler(requestResult, response, error);
}
if (409 == httpResponse.statusCode) { //needs surge confirmation
NSLog(#"Surge Conflict");
}
else
{
NSLog(#"Error In response");
}
}];
**
And response I am getting is:
{ URL: https://sandbox-api.uber.com/v1/requests } { status code: 401, headers {
Connection = "keep-alive";
"Content-Length" = 83;
"Content-Type" = "application/json";
Date = "Mon, 07 Nov 2016 11:19:35 GMT";
Server = nginx;
"Strict-Transport-Security" = "max-age=0";
"X-Content-Type-Options" = nosniff;
"X-Uber-App" = "uberex-sandbox, migrator-uberex-sandbox-optimus";
"X-Uber-Missing-Scopes" = true;
"X-XSS-Protection" = "1; mode=block";
} }
Result:{
code = unauthorized;
message = "Requires at least one scope. Available scopes: ";
}

Answer 1

I got the solution. Problem Was With My Scope input.While requesting for token,even if the account you are login is of developer, we need put scopes properly. In my case I needed request scope in token.