It is in the permissions, check the source code of the block and you'll see what terms to use for the permissions for that block. Look for something like:
// Security
pnSecAddSchema('Categoryblock::', 'Block title::');
At the start of the block script. See
this post [25] (note search terms)
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Get PhotoGallery, PayPalCart, Dynamenu, Enhanced Blocks & other mods [26]
Cape Cod [27] Travel Info...