What’s the default Office 365 email message size and how to increase?

By default, an email message you could send or receive in Office 365 is 25 MB. However, you can increase it up to 150MB. Here is how.

1. With Office 365 admin center open, go to Exchange admin center.
2. Click on recipients.
3. Highlight the display name which you want to increase the email message size. Then click on 3 dots… Select Set default message size restrictions.

4. Enter the size of sent/received message no more than 153600 KB.

5. Click OK to save the settings.