I have Exchange server 2013 environment with 3 mailbox and 2 Edge servers. I got mail flow issue that email coming from Edge servers to Mailbox servers were stuck in Queue. after looking into the Queue and got the error "451 4.7.0 Temporary server error. Please try again later." on both Edge servers.
after look into the Mailbox servers I found heavy load on the mailbox Servers. CPU and memory were reaching to 100%. So after decreasing the load on the all three servers by moving some DBs to DR site and restarting the Microsoft exchange Transport services on the mailbox servers, the load become decreased, then restart the same services on the EDGE servers as well, the Queue become on decreasing.
So the mail Queues were on both Edge servers were due to load on the all 3 mailboxes Servers on PR site not any issue with Edge Servers.
after look into the Mailbox servers I found heavy load on the mailbox Servers. CPU and memory were reaching to 100%. So after decreasing the load on the all three servers by moving some DBs to DR site and restarting the Microsoft exchange Transport services on the mailbox servers, the load become decreased, then restart the same services on the EDGE servers as well, the Queue become on decreasing.
So the mail Queues were on both Edge servers were due to load on the all 3 mailboxes Servers on PR site not any issue with Edge Servers.
