Our email hosting service has a self-policing feature that will block and suspend email accounts that attempt to send transactional or email marketing services. This includes:
- sending invoices in bulk
- sending emails individually in short periods of time that have the same subject line
- emails that contain marketing messages
- emails sent from invoicing software (QuickBooks, etc.)
These measures help protect the overall integrity of the email hosting and associated IP addresses. It also helps ensure your domain and email accounts are not blacklisted or blocked by a receiving party.
As spam and phishing email campaigns have increased in recent years, ISPs are using more aggressive filtering and security measures to combat the problem. Using your email account increases the likelihood your email and domain will be blacklisted.
If you need a solution for sending transactional emails such as invoices, find some sources and references here:
https://www.google.com/search?q=transactional+email+smtp+service
If you need a solution for email marketing, find some sources and references here:
https://www.google.com/search?q=email+marketing+service