I just setup an Exchange 2013 server hosted on the same machine as the Active Domain Controller.

I tested the connectivity of the server , I found that the mailbox can only send email to external mailbox however it can't receive any mail either from external mail or internal mail.

I ran the Exchange connectivity analyzer for inbound mail and it failed with the following message. 

> 
> The server returned status code 451 - Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX3
> 
> 
> 

I did a search on technet forum and found the following thread

<http://social.technet.microsoft.com/Forums/exchange/en-US/288e1619-ce56-4c3a-8bb1-4886835520fe/delivery-fails-the-server-response-was-470-temporary-server-error-please-try-again-later?forum=exchangesvrdeploy>

but no luck , i dont know how to set an alternative host, would somebody please help.

error details:

```
Message: Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX3 
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() 

The server returned status code 451 - Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX3 
Exception details:
Message: Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX3 
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: 3107 ms.
The server returned status code 451 - Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX3 
Exception details:
Message: Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX3 
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: 3107 ms.

```