I'm on plan Creative Cloud for individuals - Complete with Adobe Stock (one-year).
1st month when I added Adobe Stock (10 images), I was able to purchase 10 images.
Then I needed to by more I had to add a single image Plan in order to download more than 10.
So far so good.
Now I'm in my second month.
I can't download any image. this is the only message I get when I try buying!
Your monthly allocation of 10 images has been added to your account so you should be able to use them now.