I got free month of apple music for free but it doesn't work

well... I was subscribed to apple music before but when my subscription expired I got to renew it ,so I've got a free subscription for 2 months from an app (shazam) but it tells me that : "this offer cannot be redeemed with your current subscription " so I went to check my subscription but there is no subscription active there is nothing active , what should I do please I want some help:(