Failed to copy files to Macintosh_HD

I am trying to copy files from the server to Macintosh_HD (/Volumes/Macintosh_HD) via scp: scp -r username@IP:directory-path .

But it is showing an error:

Permission denied, please try again.

I am logged in as admin, and the above command is working fine while copying in /Users/home.

Kindly suggest the probable solution.