here's the result of the Exchange connectivity test at

https://testconnectivity.microsoft.com/

statuscode 451 - Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX5 .

Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX5 
Type: System.Net.Mail.SmtpException

at System.Net.Mail.DataStopCommand.CheckResponse(SmtpStatusCode statusCode, String serverResponse)
at System.Net.Mail.DataStopCommand.Send(SmtpConnection conn)
at System.Net.Mail.SmtpClient.Send(MailMessage message)
at Microsoft.Exchange.Tools.ExRca.Tests.SmtpMessageTest.PerformTestReally()

• Edited by --JayJay-- 21 hours 40 minutes ago

https://social.technet.microsoft.com/Forums/exchange/en-US/fc26dac5-d4e2-49da-903d-361ea8b85388/451-470-temporary-server-error-please-try-again-later-prx5?forum=exchangesvrgeneral

solution found:

server host file needs 

IP             server-hostname

IP             server-hostname.domain

• Proposed as answer by jim-xu 4 hours 57 minutes ago
• Edited by --JayJay-- 3 hours 50 minutes ago mis spelled

I set up a new virtual test environment with Windows server 2012 R2 and MS Exchange server 2013 SP1 on top.

Server is fully up to date by Windows Update.

A very basic configuration is made with just a few users , mailboxes, and basic email working for outgoing, incoming and internal mail.

DNS records, Routing/switching & firewall are properly configured. Incoming mail is working at moments.

On Exchange:

- Outgoing connector configured

- no additional incoming connectors configured, other than default

- Servers/DNS lookups configured

This runs fine , but after a short period (30 min.s) the incoming mail functionality is failing and the administrator eventually gets blocked from access to the ECP.

Is this a known issue for the combination of Win server 2012 R2 and Exchange 2013.

Or some missing configuration ?

• Edited by --JayJay-- 23 hours 12 minutes ago