Why can't I mount a folder via ssh?

Question

SSH

I'm trying to mount the folder of the root directory of the router:
sshfs [email protected]:/ /media/openwrt
as a result I get the answer:
remote host has disconnected
if I specifically enter the password incorrectly, it asks again, but if I enter it correctly I get the answer:
remote host has disconnected
computer Linux Mint 18.2
router TP-link 741ND protected by OpenWRT
I can't understand what I'm doing wrong

Answer 1

I mount after installing these packages with
this command:
mount.nfs -o nolock 10.10.10.7:/hdd /nfs