Error 14 in an iPhone is generated when your iPhone storage reaches its maximum capacity; it means storage is full now, and it will not be able to download or keep any more documents into its internal storage. That's when you will go through the error 14 messages in your iPhone. This can further cause the phone to get stuck at the Apple logo while updating because excessive files in a device slow down the speed of the iPhone, or even any other phone gets slowed down in such cases. It sometimes feels very annoying to have full storage, so always try to keep deleting unnecessary files.