I've been trying to download The Witcher 3: Wild Hunt for the last two days with no success. The installation keeps failing and saying there was a connection problem. Before it says this, the installation progress will stop at a certain percent for a while before it fails. What should I do about this? Is it an internet problem? A computer problem?
Thanks!

Wait till servers are fixed (Just wait some time and try it again) or download the game from your Library and install the game manually (Account - Library - Witcher 3 - left side of the pop-up you can see the game (7 parts, 1 exe-file and 6 bin-files) amd the patch (2 parts, 1 exe-file and 1 bin-file) - download what you need - double click the exe-file to install).
Galaxy is optional. You can import your game later to Galaxy if you want.

IMPORT ALREADY INSTALLED GAMES TO GALAXY

For GOG games installed using installers from the last few months (so called Galaxy-compatible installers)
Click the "+" button on top of the sidebar and select "scan and import folders" - it will find all compatible games within that folder and add them to the Client.