Please help - validate receipt using our server

I am working on our first in-app purchase and trying to use our server to verify the receipt using our server to connect to Apple's server.  I keep getting Status 21003.  Here is our Objective C  code....

 -(IBAction)NewVerifyReceipt {

NSURL *receiptURL = [[NSBundle mainBundle] appStoreReceiptURL];

    NSData *receipt = [NSData dataWithContentsOfURL:receiptURL];

    if (receipt) {

        NSString *receiptEncoded = [receipt base64EncodedStringWithOptions:0];

        // In addition we need to replace +(plus) sign for encoding

        receiptEncoded = [receiptEncoded stringByReplacingOccurrencesOfString:@"+" withString:@"%2B"];

        NSString *post = [NSString stringWithFormat:@"receipt-data=%@", receiptEncoded];

    NSLog(@"\n\n\n        POST:%@", receiptEncoded);

        NSData *postData = [post dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:NO];

        NSString *postLength = [NSString stringWithFormat:@"%lu",(unsigned long)[postData length]];

  NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];

        [request setURL:[NSURL URLWithString:@“our_server_code.php”]];

        [request setHTTPMethod:@"POST"];

        [request setValue:postLength forHTTPHeaderField:@"Content-Length"];

        [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];

  [request setHTTPBody:postData];

        NSURLSession *session = [NSURLSession sharedSession];

        NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error)     {

            NSDictionary* json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

            NSString *result = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];

            NSLog(@"result =%@",result);

            NSLog(@"json =%@",json);

            if (!error) {

                int statusCode = [[json objectForKey:@"status"] intValue];

                if (statusCode == 0) {         // Receipt-data is valid

                }

            }

        }];

        [dataTask resume];

}

Here is our server code: PHP

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL,"https://sandbox.itunes.apple.com/verifyReceipt");

curl_setopt($ch, CURLOPT_POST,1);

curl_setopt($ch, CURLOPT_POSTFIELDS, $post);

$result=curl_exec ($ch);

curl_close ($ch);

Can anyone please help?

Please help - validate receipt using our server
 
 
Q