Public Page Is Not Accessible For Sites

I created the 2 site below.

First (nodename=first,
Second (nodename=second,
But I am not able to access the public page unless add the below line in Policy.yaml in sites package.

privilegeTarget: ‘Neos.Demo:Site.First’
permission: GRANT

And I don’t want to give the all the permission to Everybody.
I just want the all public pages for both site has to be access through the frontend user.

It gives the below exception.

# Could not convert target type “Neos\ContentRepository\Domain\Model\NodeInterface”: Entity of type ‘Neos\Neos\Domain\Model\Site’ for IDs Persistence_Object_Identifier(408056f5-ab3b-4c7e-adb8-0d50be724e85) was not found"

Any suggestion will help me.

Please use the code feature to make your code easily readable.

Also it would help to see your whole policy yaml where you also define the privilege.