Outlook - Bulk Email Restrictions and Limits:

About:

This document explains why organisations enforce bulk email restriction policies in a Microsoft Intune and Microsoft 365 environment.

Why do we have a policy?

Bulk email restriction policies exist to protect the organisation’s email system and reputation. In a Microsoft 365 environment managed through Intune, email accounts are intended for business communication, not mass mailing.

Without limits, email systems can be abused intentionally or unintentionally, leading to:

• Spam being sent from company accounts
• Accounts being compromised and used for phishing
• Company emails being blocked or flagged externally
• Reduced email reliability for all users

This policy ensures email is used responsibly and securely.

What are the sending limits?

Microsoft enforces built-in sending limits across Microsoft 365 tenants. These limits may vary slightly over time, but typically include:

• A maximum number of recipients per email
• A daily recipient limit per user
• Rate limits on how many emails can be sent in a short time

These limits apply to all users and are monitored automatically by Microsoft’s security systems.

What happens if you go over the limit?

If a user exceeds the sending limits, Microsoft may take automatic action, such as:

• Temporarily blocking the ability to send emails
• Restricting the account from sending external mail
• Flagging the account for suspicious activity

In some cases, IT intervention is required to restore email functionality. Repeated violations may lead to further investigation or permanent restrictions.

Why do we have these limits?

These limits exist to:

• Prevent spam and phishing attacks
• Protect the company’s email domain reputation
• Ensure emails are delivered successfully to customers and partners
• Reduce the risk of account compromise going unnoticed

If our domain is flagged as a spam source, legitimate business emails may be rejected or sent to junk folders worldwide.

What do I do if I need to send a mail to a large group?

If you need to contact a large audience, use approved alternatives instead of individual bulk emails, such as:

• Distribution groups managed by IT
• Microsoft Teams channels
• SharePoint announcements
• Company-approved mailing or communication tools

If you are unsure which option to use, contact IT before sending the message.

How can I avoid being blocked?

To avoid sending restrictions:

• Do not send mass emails from your personal mailbox
• Avoid large recipient lists in the To, CC, or BCC fields
• Use approved distribution groups or communication platforms
• Contact IT in advance for large communications
• Be cautious of unusual sending behavior if your account may be compromised

Following these practices helps keep your account secure and ensures reliable email delivery for everyone.

And you are done 😄