I have two Macs, both running Mac OS Sierra. I can ssh from the laptop to the desktop and use Apple's screen sharing to view the desktop's screen from the laptop. I cannot mount the desktop's disks on the laptop. I have Sharing turned on, both AFP and SMB, but I cannot connect via either. I've tried connecting to the desktop via smb://, smb://.local, and directly by its local IP address (and the same for afp://). ssh <hostname>.local works, so it's not a DNS resolution issue.
The specific error I get is:
The server may not exist or it is unavailable at this time. Check the server name or IP address, check your network connection, and then try again.
Edit: I should mention that when I try to connect by selecting the machine through the Finder sidebar, it doesn't connect, and clicking "Connect As" fails before getting to the password screen.
Best Answer
Make sure you have the user enabled in sharing (File sharing/options) Then try ssh localusername@hostname.local