Hello, I have exactly the same problem.
I can play 5mn, like I can play 30mn or 1hour and gets a network crash. It seems to be completely random. Seems to happen even more with a ALT-TAB.
I’ve reset my router.
I’ve reset my IP on my PC.
Do some tricks with Battle.net.
Etc…
Nothing works at all and I lose my time.
This is the only game who does this, I have no problem with others games, and this is the first time I gets a problem like this with a game.
I’m gonna test this when I have time :