There is a 500 outgoing email hourly limit per domain. If you send over this amount in any hour, most of the e-mails will bounce back with an undeliverable error. If this occurs, it will then take some time for your account to be able to send again so we recommend waiting at least 1 hour after this issue occurs to begin sending email again.
Many of our servers have a limit of 30 POP3/IMAP checks per hour per each user's connecting IP address. If you go over this you're likely to get a wrong password error message or an error stating "login incorrect". If this occurs, please wait an hour and it will automatically unblock you. To prevent this from happening again, please make sure to disable auto checking or at least set it to something higher such as once every 10 minutes.
