Emails Sending Troubleshooting

Hi All

Just recently got osTickets to start sending emails.

I've setup the Alert and the Support Email accounts.

Thing is, the Alert Email is functioning correctly while the Support Email isn't.

I've tested both accounts to make sure that they are working - both send and receive emails well using Outlook.

Is there anything I can check to make sure my setup in osTickets for the Support Email is correct?

btw, the both emails are on the same Exchange server and use the same settings.

Thanks in advance for any responses. :)