this was during a promotion, Genshin can deactivate the keys at any time. the other issue could be that you dont meet the needed lvl rank 10.
Genshin Impact 1.2 Key Expired
There were about 1,500 keys left when I redeemed the Genshin Impact 1.2 key from Alienware, but the Genshin website said the code expired when I entered it on the Genshin website just now. Did this happen to anyone else?
Genshin impact discontinues keys every few days after they are released. Not sure about giveaway keys but they usually remove keys all the time.
Also, if you activated another 1.2 version key on your account, then all the future 1.2v keys will say they are expired :(