NSString *username = @"admin";
NSString *password = @"test";
NSString *authString = [NSString stringWithFormat:@"%@:%@",
                        username,
                        password];

// 2 - convert authString to an NSData instance
NSData *authData = [authString dataUsingEncoding:NSUTF8StringEncoding];

// 3 - build the header string with base64 encoded data
NSString *authHeader = [NSString stringWithFormat: @"Basic %@",
                        [authData base64EncodedStringWithOptions:0]];

// 4 - create an NSURLSessionConfiguration instance
NSURLSessionConfiguration *sessionConfig =
[NSURLSessionConfiguration defaultSessionConfiguration];

// 5 - add custom headers, including the Authorization header
[sessionConfig setHTTPAdditionalHeaders:@{
                                          @"Accept": @"application/json",
                                          @"Authorization": authHeader
                                          }
 ];

// 6 - create an NSURLSession instance
NSURLSession *session =
[NSURLSession sessionWithConfiguration:sessionConfig delegate:self
                        delegateQueue:nil];

// 7 - create an NSURLSessionDataTask instance
NSString *urlString = @"http://test.myserver.am/api/authentication/Login?username=admin&password=test";
NSURL *url = [NSURL URLWithString:urlString];
NSURLSessionDataTask *task = [session dataTaskWithURL:url
                                    completionHandler:
                              ^(NSData *_Nullable data, NSURLResponse *_Nullable response, NSError *_Nullable error) {
                                  if (error)
                                  {
                                      // do something with the error

                                      return;
                                  }

                                  NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
                                  if (httpResponse.statusCode == 200)
                                  {
                                      arrTokenData = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

                                      [self getDomain];
                                  } else {
                                      // failure: do something else on failure
                                      NSLog(@"httpResponse code: %@", [NSString stringWithFormat:@"%ld", (unsigned long)httpResponse.statusCode]);
                                      NSLog(@"httpResponse head: %@", httpResponse.allHeaderFields);

                                      return;
                                  }
                              }];

// 8 - resume the task
[task resume];

[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];

        NSString *authValue = [arrTokenData valueForKey:@"Token"];

        //Configure session with common header fields
        NSURLSessionConfiguration *sessionConfiguration = [NSURLSessionConfiguration defaultSessionConfiguration];
        sessionConfiguration.HTTPAdditionalHeaders = @{@"bearer": authValue};

        NSURLSession *session = [NSURLSession sessionWithConfiguration:sessionConfiguration];

        NSString *url = @"http://test.myserver.am/api/mobile/LookUps/getuserdata";
        NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:url]];

        NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
            [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
            if (!error) {
                NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
                if (httpResponse.statusCode == 200)
                {
                    NSDictionary *jsonData = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers|NSJSONReadingAllowFragments error:nil];

                    //Process the data
                }
            }

        }];
        [task resume];