You can automatically receive email notifications when you server storage reaches certain threshold from the Settings > Storage screen:
1. Click the Gear icon 
near the top-right corner of the dashboard.
2. Select Setting.
3. Select the Storage tab:
4. Set the EMAIL MIN SPACE THRESHOLD. This settings specifies when you will receive the notification email. Note that, this setting must be equal to or greater than MIN SPACE THRESHOLD. If you enter 0, you will disable the email notification.
5. You can set who will receive the email notification in the NOTIFICATION EMAILS field.
6. You can disable the notifications temporarily (for 12 hours) by clicking the DISABLE EMAIL NOTIFICATIONS > FOR NEXT 12 HOURS button.