
Hello ! I'm Aymeric, an independent advisor, and I'm here to help !
This offer is only valid for Spotify accounts that have never subscribed to Spotify Premium. Is this the case for you ? If you've already subscribed to Spotify Premium, you won't be able to activate the free three months. You'll see an error message.
If you're sure you meet all the conditions, I'd advise you to contact Spotify support directly, who will be able to pinpoint the source of the error.
Please let me know if you have any other question !