I suppose that's the output for an earlier question of yours where you stated some delivery issues. As I can see here there is always a five minute gap between Delivery start and the timeout error, so this is most likely a bandwith shortage on your or the recipients end. "Bad Connection -Timeout" basically states that the message could not get delivered within the five minutes timeframe AsyncOS allows for delivery. Those five minute setting is a fixed value that cannot be configured.
My suggestion would be that you configure a destination control entry (GUI: Mail Policies->Destination Controls) for the affected domain(s), and use a low value for the concurrent connections limit. Low value in this matter actually means much lower that the default 500 concurrent connections, try with something like 5 or even less.
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...
[toc:faq]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 and UDP are I...