Email Send Problem

Hi,

I have a little mail problem. When sending mail from the server, it doesnt send the mail. Delays the mail and puts it in queue. and loops, unable to send. When I click the flush queue button from the “domain.com:8090/emailPremium/mailQueue” section, mails are sent. The mail server is open now and I have no problem receiving mail. When sending e-mails, it queues, but when the queue is empty, those mails are also sent. how can i fix this problem?