Sometimes Outlook might have problems sending a message. There may be various causes- corrupted PST, AV scanner etc. The message, instead of going to the Sent Items folder, sits in the Outbox indefinitely.
To remove it you can use a free tool called MFCMAPI
Local Continuous Replication is a cost effective and quick way of backing up Exchange server data. The following article describes the steps required to configure Local Continuous Replication. Also, the article tells you how to restore from a backup created using LCR.
CodeTwo is a software development company with over 51,000 customers around the world and a well-established position in Microsoft Exchange Server, Office 365 and Outlook communities.
Our products expand the capabilities of Microsoft Exchange, Office 365 and Outlook in terms of email content, flow & signature management, mailbox migrations and backups, collaborative work, and more. We aim to provide top-level technologies, without sacrificing usability and efficiency.