Why has one of my users got this bounce message when emailing 250 people
'Sender address rejected: Proofpoint Essentials Terms of Service: burst rate limit exceeded, you may need to request activating a 'bulk sender' profile.'
This is flagging that the terms of service have been breached as the user is trying to send bulk email via the Proofpoint service. Proofpoint Essentials is a business email platform, users should use an outbound campaign management platform for bulk emails such as;
The Proofpoint Administrator Guide has further information and is available for download at the link below. Refer to p9 - Sending Message Limit. Proofpoints online knowledge base also has some help with this article.
However, if the organisation requires higher outbound volumes for specific senders you can request an exception to be made by raising a support ticket here.
Alternative strategies are;
- Ask users to keep within the burst limit of 100 emails per 10 minutes and 500 per day
- Use an outbound SMTP route for bulk, such as SendGrid or MailGun (from Cleartext Systems).