Outbound Caller ID Blocking prevents your number from being available when you place calls.
Anonymous Call Rejection will block any incoming calls that are preventing the caller's number from being available. When both of these options are enabled on your line, dialing your home phone number from your home line will result in the call being blocked, and therefore you will not be able to use this method to listen to messages. Instead you will need to dial the Voicemail remote access number (it can be programmed as one of your speed dial numbers). For instructions, please refer to the question "How do I retrieve my Voicemail?"