CB has no functionality to delay emails. Your mail server would be the one delaying the emails. You'll need to talk with your host to see why that is.

CB uses whatever mailer you configure in Joomla global configuration. CB has no functionality to delay emails. Once an email is triggered it is sent to your mail server immediately. Your mail server would be the one delaying sending of the emails for whatever reason and you'll need to talk with your host regarding that to figure out what's going on. It could be as simple as a spam protection in their mailer requiring you to make your emails more unique.