Thank you for reaching out to the Community.
If you hear and see ads while playing music, most probably you've accessed a different account from your Premium one.
In this case, we suggest you access your Account Overview and check the status of your subscription. If it shows as free, then your Premium account is registered under different information. You can find more info here.
If it shows as Premium, please log out of the app and access again using the Username from the Account Overview and your password.
Let us know how this goes!
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