Configuring preferences and options in Outlook.com
Outlook.com enforces sending limits to help prevent spam. The number of recipients allowed can be temporarily lower for newer accounts or accounts that have not yet established credibility.
Supported Outlook.com limits for Microsoft 365 subscribers are:
- Daily recipients: 5,000
- Maximum recipients per message: 500
- Daily non-relationship recipients: 1,000
A non-relationship recipient is someone who has never been emailed before. Limits can be lower for non-subscribers, and can vary based on usage history.
To improve or restore the allowed sending volume:
- Add recipients to Contacts in Outlook.com.
- Send to smaller batches instead of large groups.
- Communicate frequently with Contacts to establish credibility.
- Make sure account information is fully updated, including phone number and alternate email address.
- Update profile information such as profile name, photo, date of birth, and gender.
- Use a strong password with upper/lowercase letters, numbers, and special characters.
- Use the Microsoft Authenticator app.
If the account was recently created, the lower sending quota is temporary and is increased as credibility is established.
Also check these common causes if sending fails:
- Attachments larger than 25 MB cannot be sent through Outlook.com.
- Email signatures can sometimes interfere with sending; remove the signature and try again.
- If a recipient is not receiving messages, ask them to add the address to their Safe senders list.