iOS Zip downloaded successfully but failed to extract the same programmatically

I need to download a zip from the given url and When i am doing the operation

BOOL status = [reply writeToFile:dataPath atomically:YES];

the zip is downloaded but seems corrupted in an environment (by means with one deployment environment in machine first and installing to iOS device it works fine while with another machine and installing to iOS device it fails.)

Also i observed that when i try to open the zip directly it has size of 33 kb but fails to extract and seems corrupted.

Please help on the same. here reply is (NSData *)reply