Issue in POST request using Objective C - objective-c

Question

i'm hiting an API in postman there i get result fine, this how i'm making POST request in postman,
But when i hit same API in my application using objective c, i got errors, i'm passing parameters fine but result is not coming true, i'm confuse that why it is not showing results true, This is my code for POST request,
- (void)sendRequest
{
NSArray *userArray = [NSArray arrayWithObjects: #"ishaqshafiq#hotmail.com",nil];
NSDictionary *emp = #{#"lstUsers": userArray,
#"message":#"Your Order is Booked",
#"data": #{
#"type":#"text",
}};
NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration];
NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject delegate: nil delegateQueue: [NSOperationQueue mainQueue]];
NSString *urlLinkA=#"http://sajjenweb.azurewebsites.net/api/HubConnection/PostMobileNotification";
NSURL * url = [NSURL URLWithString:urlLinkA];
NSMutableURLRequest * urlRequest = [NSMutableURLRequest requestWithURL:url];
NSString *parameters = [NSString stringWithFormat:#"%#",emp];
NSLog(#"parameter %#",parameters);
[urlRequest setHTTPMethod:#"POST"];
//[urlRequest setHTTPBody:[parameters dataUsingEncoding:NSUTF8StringEncoding]];
NSURLSessionDataTask * dataTask =[defaultSession dataTaskWithRequest:urlRequest
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
NSLog(#"Response:%# ", response);
NSLog(#"Error is %#",error);
NSDictionary *dictionary = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:&error];
// NSLog(#"DDD %#",dictionary);
NSString *res = [dictionary valueForKey:#"recipients"];
NSLog(#"RR: %#", res);
NSString *msg=#"Successfully Submitted";
UIAlertController *alert = [UIAlertController alertControllerWithTitle:#"Success"
message:msg
preferredStyle:UIAlertControllerStyleAlert];
int duration = 2; // duration in seconds
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, duration * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
[alert dismissViewControllerAnimated:YES completion:nil];
});
}];
NSLog(#"network error :");
[dataTask resume];
}