Exchange Server 2013: Not Sending and Receiving email

Hello, 

I have a new Exchange Server 2013 install single node and i am having problems sending and receiving email.

When testing from https://testconnectivity.microsoft.com/ it fails at the last step when it tries to send a test email. I get the following response;

The server returned status code 451 - Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX4

Exception details:

Message: Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX4 
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()

Any Suggestions?? Thank you..