Do you limit the amount of mails I can send per hour? Print

Yes, we do. The amount of mails sent per hour is limited to 1500 per user. We do this to minimize the impact of spammers who may sign up with us and get by our initial checks.

Once you've hit this limit, mail will bounce with the 'unrouteable domain' error in the bounce message. The only way around this error is to wait until the hour is up.