Cannot edit customer metafields form Customer Account API

[Caleb_Martin]

I am making a feature where customers can view a recipe and favorite it. The recipe then saves to a metafield on the customer. But when I use the metafieldsSet mutation, I always get this error →

{
     field: [ 'metafields', '0', 'ownerId' ],
     message: 'Owner type Access to this namespace and key on Metafields for this resource type is not allowed.',
     code: 'DISALLOWED_OWNER_TYPE'
   }

Here is my mutation

const newFavorites = await context.customerAccount.mutate(
        METAFIELDS_SET,
        {
          variables: {
            metafields: [
              {
                key: 'favorites',
                namespace: 'custom',
                ownerId: 'gid://shopify/Customer/5862292226223',
                type: 'json',
                value: JSON.stringify(favorites),
              },
            ],
          },
        },
      );

And here is my metafield setup I made on Customers.

So why won’t it let me edit the metafield? It has the correct permissions to be edited by the Customer Account API so what else could it be?