I can sftp to usegalaxy.org using FileZilla from my local machine here so there would appear to be no problem with the authentication - I can also transfer a file using the Filezilla GUI and pick it up at Galaxy and add it to my store.
Problem comes when I try doing the same thing from our SGE cluster command line using sftp - password appears to be getting rejected. I’ve tried removing and reaccepting the keys in my .ssh folder and various combinations of the sftp/sshpass command but always this:
 here’s my solution YMMV.
The lftp program mentioned in the Galaxy tutorial would work for me locally on Ubuntu or Ubuntu app running under Windows 10. There’s no sudo privileges for users on our cluster so workaround is to wget the lftp source code, ,/configure, make, make install then update and source ~/.bashrc with whatever path you now have lftp in.
Works straight out of the box following the tutorial after that - Happy Days.