When I send out emails, they bounce back saying "unroutable domain".
This error message could be the result of several issues including:
1. The email address that you entered as the recipient was invalid.
2. You have exceeded the maximum outgoing hourly email quota on the server.
Our shared servers are set to only allow 200 outgoing emails per domain, per hour. This prevents spam abuse and clogging up the mail server which negatively effects others on our shared servers. If you have emailed roughly 200+ people in the last hour or a script on your website has, please wait a while and then try to resend it. If you have a dedicated server or VPS, you will not be affected by this problem and will only be affected by point 1 above.
If you do need to send lots of emails regularly, see our article on "Operating mailing lists" because there are some important things you need to be VERY aware of if your trying to send out mass emails regularly, and on shared servers, you need to batch send them so as not to backup shared servers mail queues and affect other customers, and also some important legal requirements for sending mass emails.