Restore deleted items from Outlook on the web.
When calendar, email, and tasks are deleted, they are moved to the Deleted Items folder. Items are automatically purged from the Deleted Items folder after 30 days. Deleted items can be recovered from the Deleted Items folder for up to 14 days after they are purged. Items recovered will be moved to their default locations: emails to the Inbox, calendar items to Calendar, contacts to the Contacts folder, and tasks to the Tasks folder.
1. Right-click the Deleted Items folder and then click "Recover deleted items..."
2. Select the item(s) you want to recover and then click the "Recover" button.