Dears,

we have urgent issue all email form internal and external stayed in the Queue for one hour then delivered for the users

this below error i found in the queue in error message tab

"Last Error"
"mailbox database xxxxxxxxxx" "SMTP Delivery to Mailbox" Connecting 16  "[{LRT=6/1/2015 11:11:43 AM};{LED=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 xx.xx.xx.xx:475};{FQDN=mailbox database xxxxxxxxx};{IP=xx.xx.xx.xx}]"

Please Help Me really its a urgent issue

Hi,

Check your next hop (edge or gateway servers) are they healthy. The issue seems to be the next hop is not responding, either it is down or not responding.

do telnet to the next hop server and verify the ports are listening

Hi,

Are you experience same issue when sending message? Also confirm what you have done before this issue occur?
Do you have deploy Edge or Firewall in your environment?

Please run Message Tracking log to filter message delivery process. Doing this way, we can find the next hop which deliver message again.
Meanwhile, point that xx.xx.xx.xx:475};{FQDN=mailbox database xxxxxxxxx};{IP=xx.xx.xx.xx}] is a IPv6 address. Please open DNS Manager to ensure whether this a relevant record for this.
If so, please remove this IPv6 DNS entries then switch to problematic server to disable IPv6. Finally, restart Exchange server for testing.