Hey @geceace, thanks for reaching out to the Community!
Could you try getting started with Premium for Family here, using a different browser? A private/incognito browser will work too.
If you're still getting the same error message, please let me know.
Let me know how this goes 🙂
Help others find this answer and click "Accept as Solution".
If you appreciate my answer, maybe give me a Like.
Note: I'm not a Spotify employee.