type as a root user ifconfig usb0 192.168.2.14 up then do this ping 192.168.2.15 if pings you are ready to go for SSH otherwise check ur phone developer mode enabled again
alternative way that gives u windows like view is to use nautilus in linux simple just click computer icon in your linux desktop then the nautilus window opens click files in the nautilus menu then click connect to server then enter these respectively chose SSH IP: 192.168.2.15 user: root password: nemo now you have folder view of ur sailfishOS goodluck