I am also having this issue. My brother plays Raid and I just set up a new account on his phone while he signed in on his laptop.

Not able to get promo codes like GetUDK or Mordecai to work at all. Is this because I created an account on his phone? It's a new email address which is my own, and I do have separate player ID, so confused as to why the codes won't work!

if the device have had the app downloaded before it doesnt see you as a new player and the promocode wont work.