Leviathan dlc, download corrupt

I downloaded the Leviathan dlc. At the end a message popped up saying the download is corrupt (it had advice on what to do next, but it closed before I could read it).

When I start the game I get a message saying "load failed, cannot connect to server" when it checks downloadable content.

The game still plays, but when I follow the Leviathan storyline the Pylos nebula doesn't appear on my galaxy map.

What do I do?