I have an Exchange 2010 installed in my environment and I has configured the Receive Connectors to enable POP3 and IMAP connections in Authorized Tab.
I have configured the Outlook Express but when the user try to send email the following message about relay appears:
The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'firstname.lastname@example.org'. Subject 'Test', Account: XXX, Server: 'test.lab.local', Protocol: SMTP, Server Response: '550 5.7.1 Unable to relay', Port: 25, Secure(SSL): Yes, Server Error: 550, Error Number: 0x800CCC79
I need some help to solve that problem. If anyone can help me I appreciate.