Exchange 2013 Delivery is delayed

anybody have any suggestions on troubleshooting this issue below:

Diagnostic information for administrators:

Generating server:
Receiving server: (
Remote Server at ( returned '400 4.4.7 Message delayed'
10/23/2015 9:59:27 PM - Remote Server at ( returned '441 4.4.1 Error encountered while communicating with primary target IP address: "Failed to connect. Winsock error code: 10060, Win32 error code: 10060." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts. The last endpoint attempted was'

I have rebooted our on premise Mailbox servers but not our client access servers yet.
GrizNation23IT DirectorAsked:
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Schnell SolutionsSystems Infrastructure EngineerCommented:
That error is related to communication between your server and Exchange Online Protection.

Most of the time it happens because of a lack of communication from your system to the MS Internet service or after not been accepted by the EOP servers (i.e. spam categorization, many messages send, non compliant IP address, etc).

Could you please describe your environment, it looks that your exchange server uses EOP (Exchange Online Prtection) to deliver external email. How is it?

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GrizNation23IT DirectorAuthor Commented:
Was communication error, our Firewall required reboot, after that, we had a numerous emails complete to their recipients, but would anybody have a clue why firewall would affect if EOP is viewable from inside network and all other network traffic was good in/out (internet).
Schnell SolutionsSystems Infrastructure EngineerCommented:
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Windows Server 2012

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