Error Uploading File :-1: linker command failed with exit code 1 (use -v to see invocation)

I created a Pdf file which prints and emails without any problems and im trying to upload to my dropbox apps folder.  This is my first dropbox App and I need help please.

I keep getting this error : -1: linker command failed with exit code 1 (use -v to see invocation) 

My Code is as follows:

Appdelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 

    //Begin Dropbox

    [DBClientsManager setupWithAppKey:@"<APP_KEY_REDACTED>"];

   DBUserClient *client = [[DBUserClient alloc] initWithAccessToken:@"<ACCESS_TOKEN_REDACTED>"];    

     return YES;

}

- (BOOL)application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary<UIApplicationOpenURLOptionsKey,id> *)options {

    DBOAuthResult *authResult = [DBClientsManager handleRedirectURL:url];

    if (authResult != nil) {

        if ([authResult isSuccess]) {

            NSLog(@"Success! User is logged into dropbox.");

        } else if ([authResult isCancel]) {

            NSLog(@"Authorization flow was manually canceled by user!");

        } else if ([authResult isError]) {

            NSLog(@"Error: %@", authResult);

            

        }

    }

    

    return NO;

}

 

 

Viewcontroller.m

    DBUserClient *client = [DBClientsManager authorizedClient ];

    NSData *fileData = [@"yourPDF.pdf" dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:NO];

    

    DBFILESWriteMode *mode = [[DBFILESWriteMode alloc] initWithOverwrite];  

    [[[client.filesRoutes uploadData:@"/test/path/in/Dropbox/account/yourPDF.pdf"

                                mode:mode

                          autorename:@(YES)

                      clientModified:nil

                                mute:@(NO)

                      propertyGroups:nil

                             strictConflict:nil

                            inputData:fileData]

          setResponseBlock:^(DBFILESFileMetadata *result, DBFILESUploadError *routeError, DBRequestError *networkError) {

              if (result) {

              NSLog(@"%@\n", result);

          } else {

              NSLog(@"%@\n%@\n", routeError, networkError);

          }

      }] setProgressBlock:^(int64_t bytesUploaded, int64_t totalBytesUploaded, int64_t totalBytesExpectedUploaded) {

          NSLog(@"\n%lld\n%lld\n%lld\n", bytesUploaded, totalBytesUploaded, totalBytesExpectedUploaded);

      }];