The way that I was setting up my keys was wrong.
Also, the sFTP server was set up with a chroot jailed user and I think that was set up wrong which was keeping me from running the ssh-copy-id command.
I removed the chroot stuff and then ran the following and now all is well. I can now add the...
sFTP server - Oracle Linux 7
Linux client - Oracle Linux 7
I've created an sFTP server, first time doing this.
I think it works as I can log in to my sFTP server using the command $ sftp sftp_user@sftp_server_IP - and then enter the correct password, and I'm logged into sFTP.
I have ssh...