anybody have any suggestions on troubleshooting this issue below:
Diagnostic information for administrators:
Generating server: server.domain.com
Receiving server: Domain01b.mail.protection.outlook.com (xxx.xxx.xxx.xxx)
Remote Server at domain01b.mail.protection.outlook.com (xxx.xxx.xxx.xxx) returned '400 4.4.7 Message delayed'
10/23/2015 9:59:27 PM - Remote Server at domain01b.mail.protection.outlook.com (xxx.xxx.xxx.xxx) 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 xxx.xxx.xxx.xxx'
I have rebooted our on premise Mailbox servers but not our client access servers yet.