Safari won't permit export of bookmarks

I am trying to export Safari bookmarks. I have gone to File/Export Browsing Data to File and selected only Bookmarks from 5 options, and then selected my main profile, then clicked 'Download' button. Safari has a pop-up window requesting my "password for the user". I enter the password, and am denied the request because "Authentication is disabled".

I have cleared cache/cookies and restarted Safari. I have restarted the computer. I have tried using a New Private Window. None of these were successful.

Thanks in advance for advice.