Good thinking! I always assume that the default Site and Content Rule is enable, which allows access to all sites and all content unless there is an explicit deny rule in place.
However, if you have disabled the default rule, then you have to create explicit allow rules in order for machines/users to access any particular site or content.
I does sometimes take a while for the machine to update the configuration. One way to speed this up it to restart the service in question.
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