The servers are set to limit the number of outgoing emails from an account to 50 per hour. This is a safeguard against possible spammers which minimises any impact of SPAM being mass mailed out. Emails that exceed this limit will be queued and delivered later. If you are using mailing list software and have a list with more than 50 users, you should throttle the number per hour in your mailing list software to less than 50 per hour. If you would like this limit raised for your domain please contact support.
