I'm connecting to my university's VPN so I can connect to the network drive. The VPN seems to be working fine and I can connect to the drive by typing the address into Nautilus and entering my login details:

smb://139.___.___.140/home

However, this fstab entry doesn't work:

//139.___.___.140/home /media/___ cifs domain=CS,username==___,password=___,uid=sai,gid=sai  0 0

Nor does manually mounting it:

sudo mount -t cifs //139.___.___.140/home /media/___ -o domain=CS,username=___,password=___,uid=sai,gid=sai,user

The only error it gives is:

mount error(112): Host is down
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

It's obvious the host isn't down since I can view the share from Nautilus.

Why is Nautilus mounting it fine but not the normal mount command? What could cause this error?