Please check your network connection

So I downloaded Mop today and wanted to launch it.
But then it says the following:
Data\itemtexture.MPQ: Cannot stream required archive data. Please check your network connection. For more information, see: https://battle.net/support/article/6250
How do i fix this?

Download the full, not minimal client.

How big is it?
I downloaded the 27gb file with Bittorrent

Idk how big it is, I don't play MoP. I know that there's minimal client and a full one.