I have the same problem.
Also, I asked for help through the EA app.
I hope they fix it because if we can't buy the new expansion before 12 April (I think) we can't have the bonus content.
It never happened before in Origin'. It seems it's happening in every DLC from the Sims 4.
Hope they solve it fast.
Also, I went to the Sims 4 website and tried to buy something from there, through the EA app for Windows. It shows an error.
However, inside the game, I tried to buy the werewolves pack, and it seemed ok.
(I didn't buy it because I'm not a fan of supernatural gameplay, but try this method, maybe it is a little trick that helps).
I think I'll wait for the new expansion to come out. And I'll try the same thing.
