This article describes a scenario where you click on List management under Services > Anti-Spam, You are unable to see the Approved and Blocked Senders Lists entries.
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In most of the cases when you cannot display the Approved and Blocked Senders Lists , it's because you still need to click Search Tab in order to display the result.
Note: The List management option is a domain base option which can be found under Services > Anti-Spam, Swap the view from Global settings to the domain you would like to apply the settings for as shown below :
More Information about User Level Approved and Blocked Senders List