Can't register Cities Skylines: After Dark key

[callmewoof]

I bought my After Dark key from GMG today, and it was delivered right away. It applied to my Steam account just fine, and I can play the game. But here on the Paradox forums, when I go to register the game, it says my game key doesn't work for a registration code. I've got a bunch of other games registered to my account including other game's DLCs (I'm looking at you, EUIV). Is there something else I need to do to register it here that I'm missing? Thanks!

 

[IcratoX]

Since this involves privacy sensitive information (registration keys), could you please open a ticket at our helpdesk? https://paradox.zendesk.com/hc/en-us

 

[callmewoof]

Thank you, doing that now. I appreciate the quick response!