Ok. You used "every time" in your post. So I can say it happens to you not only when you are trying to update to Heavesward, right? I had similar problem trying to update to HW at "hard servers times" when zillions were going to do the same and all I saw was the error every now and then, so I justs used the torrent link some good guys were seeding. But we are talking of "every time" now and all I could advise is to try using wired connection in case you are using wireless one. I heard it solved your problem for many users around the globe.