Two days back i had an issue in my mail server. In the evening suddenly there were no mail flow for around 30 minutes. When i logged in to the admin console i found around 900+ mails listed down in Active queue. The mail delivery was happening but it was very slow.

During this time one of my alert mechanism malfunctioned and sent around 500 mails within minutes. I don't know if my mail server doesn't have the the capacity to receive that much mails at the same time. Can anyone suggest me on how to ensure my settings related to this issue are fine.