Every time I try and Redem the DLC it sends me to a 404 page

It's the same for me.

They FIxed the problem now.

Says me i can't have it because i don't own endless space 2 but i have it, steam sync, anyone have this too?

Hello Cerclerouge,

To know if you own ES2, we're directly making an api request to steam. Sometimes, we're not receiving the correct data. We will investigate on that but in the meantime, you should try again several times if it's still not working (and maybe wait a little between the attempts) :)

Tryed today and still can't redeem, and now the offer seems to have ended, lucky me.^^

Sorry you missed it! We are doing giveaway from time to time, so keep posted! In the meantime I'm sure there is still a lot of content in ES2 you can enjoy (or you can follow the regular updates on humankind)!