I am unable to backup my storage when I have subscribed the plan also

iPhone 12 mini

iPhone 12 Mini is available with 64GB or 128GB or 256GB of space.

Check your iCoud+ plan -> Go to -> Settings -> your name -> iCloud -> if you see 50 GB (or 200 GB or 2 TB) then you have an iCloud subscription.

If you have an iPhone 12 Mini with 64GB or 128GB of space, you need iCloud+ plan 200 GB.

If you have an iPhone 12 Mini with 256GB of space you need iCloud+ plan 2 TB.

See ⤵️

Use iCloud on iPhone -> Use iCloud on iPhone – Apple Support (UK)

Manage your iCloud storage -> Manage your iCloud storage - Apple Support

The information that you are looking for exists in this article that you were reviewing earlier 👉 If you can't back up to iCloud - Apple Support

What happens when you attempt to backup your iPhone to iCloud? Do you see any error notifications on your screen?

Axel F.