macOS NSHTTPURLResponse statuscode returns 0 . 3 Out of 10 machines returns 0, in the rest

-(int) GetData : (NSString *) urlstr : (NSData **) bufferdata
{
     int retcode =0;
     NSError *errorobj = nil;
     NSHTTPURLResponse *httpresponse;
     NSData *buffer;
 
     @try
      {
              retcode = 0;
 
              NSLog(@"url string:%@\n",urlstr);
 
              NSURL *urlobj = [NSURL URLWithString: urlstr];
              NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:urlobj cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:30.0];
 
              [request setValue:@"close" forHTTPHeaderField:@"Connection"];
 
              [NSURLRequest setAllowsAnyHTTPSCertificate:YES forHost:[urlobj host]];
 
              buffer = [NSURLConnection sendSynchronousRequest:request returningResponse:&httpresponse error:&errorobj];
 
              self->httpStatusCode =[B] [httpresponse statusCode];[/B]
 
              [B]NSLog(@"Http response status code: %i: Description:%@\n",self->httpStatusCode,[NSHTTPURLResponse localizedStringForStatusCode:self->httpStatusCode]);[/B]
 
              if(self->httpStatusCode == 200)
              {
                  *bufferdata = buffer;
                  isconnectionSuccess = TRUE;
              }
              else {
                  *bufferdata = nil;
                  isconnectionSuccess = FALSE;
                  retcode = 1;
              }
 
              //errorobj will be set to some only if intended response is received
              if (errorobj)
              {
                  retcode =  [errorobj code];
                  NSLog(@"Error Description: %@\n", [errorobj localizedDescription]);
                  isconnectionSuccess = FALSE;
              }
      }
     @catch (NSException *exp) {
     NSLog(@"GetData: Exception occurred: %@ :reason: %@\n", [exp name],[exp reason]);
      retcode = ERROR_FAILURE;
      }
 
     return retcode;
 
}

Http response status code: 0: Description:server error
Error Description: Could not connect to the server.