Good Evening,

I am running into an Intermittent receive error on Exchange 2013 RU 8 on Windows 2012.  Messages will randomly error with :

 The server returned status code 451 - Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX5
Exception details:
Message: Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX5
Type: System.Net.Mail.SmtpException
Stack trace:
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()

Elapsed Time: 21538 ms. 

Exchange receive logs show the following:

mail.hulbertassociates.com Microsoft ESMTP MAIL service ready at <RegionalDay-Date-24HourTimeFormat> <RegionalTimeZoneOffset>,

 

EHLO www.testexchangeconnectivity.com,

 

SMTPSubmit SMTPAcceptAnySender SMTPAcceptAuthoritativeDomainSender AcceptRoutingHeaders,Set Session Permissions

 

250-mail.hulbertassociates.com Hello [157.56.138.143],

 

250-SIZE 104857600,

 

250-PIPELINING,

 

250-DSN,

 

250-ENHANCEDSTATUSCODES,

 

250-STARTTLS,

 

250-AUTH NTLM,

 

250-8BITMIME,

 

250-BINARYMIME,

 

250 CHUNKING,

 

MAIL FROM:<Admin@TestExchangeConnectivity.com>,

 

SMTPSubmit SMTPAcceptAnySender SMTPAcceptAuthoritativeDomainSender AcceptRoutingHeaders,Set Session Permissions

 

receiving message

 

250 2.1.0 Sender OK,

 

RCPT TO:<jparks@hulbertassociates.com>,

 

250 2.1.5 Recipient OK,

 

DATA,

 

354 Start mail input; end with <CRLF>.<CRLF>,

 

Proxy destination(s) obtained from OnProxyInboundMessage event

 

Message or connection acked with status Retry and response 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 65.102.233.138:2525"

 

451 4.7.0 Temporary server error. Please try again later. PRX5 ,

 

Remote(SocketError)

I am at a loss at the moment.  Any suggestions would be appreciated.

Check your event logs first and see if you are getting any backpressure events

Check the drive where you have transport queue and see if it has free space

Check your transport service 

Hi,

Please try the following method to solve this issue.

1.     Browse to the hosts file. It is located in C:>Windows>System32>Drivers>etc

2.     Edit the host file and add entrys for your Exchange 2013s IP and its host name, for example.

192.168.1.5 server
192.168.1.5 server.domain.local

3.     Then restart "Microsoft Frontend Transport" and "Microsoft Exchange Transport" services.

Similar thread

https://social.technet.microsoft.com/Forums/lync/en-US/6218870f-f67f-4655-bd03-68b8fa722fc2/the-server-response-was-470-temporary-server-error-please-try-again-later-prx3?forum=exchangesvradmin

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

Best Regards.