The entry in custom URL should be .facebook.com since * (asterisk) is not a valid entry in the site section, but it is acceptable in the regular expression section.
I believe you are trying to block all social networking category, but only allowing twitter and instagram. If this is the case, you need to create a new custom URL list with CN for twitter and instagram and apply it to the decryption policy with permission to monitor or pass through.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...