Email Default Sending Rate limit on HIS hosted mail servers
By default our mail servers (Plesk or Zimbra) have a rate limit suitable for general email usage.
If you need to send at a faster speed, or to more than 100 recipients at a time please contact us and we'll let you know how we can help you.
We can host a Mailing List for you, or you can use a 3rd party Mass-Mailer, such as Constant Contact or MailChimp.