The easyname mail servers (SMTP) limit the sending of emails as follows:
If you use PHP or sendmail on our web servers, the following limits apply:
To prevent the sending of spam, the following rule applies: As soon as a mailbox produces more than 15 bounce messages within one hour, the mailbox will be blocked for one hour (no emails can be sent). If it exceeds 60, the mailbox will be blocked for 24 hours.