How to clear / delete message queue. I'm not sure what happened buy Office365 SMTP outgoing port automatically went back to default 465 instead of 587. Now I have queued message for the past 3-4days as soon as I fixed the port messages started going out. I don't want to send these message , Is there a way to delete these queued messages ? These messages are no longer in Office365 inbox which means Alert Central already processed it but due to wrong/incorrect SMTP port setting they are all stuck in some queue. I will appreciate if someone can help in clearing the current queue.
Also I'm not sure why SMTP port keeps in reverting back to default 465 after few days from 586.