Outlook cannot open DBX emails because DBX was the storage format of Outlook Express. To view those emails in Outlook, you need to change the DBX mailbox into PST first, then add the PST file in Outlook.
Start with a duplicate copy of your DBX backup, not the original folder. If the files are from an old PC, check names like Inbox.dbx, Sent Items.dbx and any custom folders so you know what should appear later.
When Outlook refuses DBX files, GainTools DBX to PST Converter Software gives a proper conversion route by reading the Outlook Express mailbox, showing email preview and creating a locally saved PST that Outlook can open. After conversion, check sender details, dates, attachments and folder names before using the PST as your main archive.
The free demo is useful for checking few emails from each DBX folder before full conversion.
