16.04 CIFS "Host is down" but they are not

After many tests adding vers=1.0 in the mount line seems to fix the problem. The mount works now on Ubuntu 17.10 like it did for years on older Ubuntu releases.

I'm facing the same problem. It seems it has something to do with newest Kernel versions and samba.

I've managed to solve this by adding vers=2.0 at mount commands (or a the end of each fstab line)

I've faced the same problem myself, I wanted to auto mount using the method found in the Ubuntu wiki (https://wiki.ubuntu.com/MountWindowsSharesPermanently) although I've got the same problem as stated above: mount error(112): Host is down

The thing is what helped me is adding vers=3.0 at the and of the options:

//servername/sharename /media/windowMBsshare cifs credentials=/home/ubuntuusername/.smbcredentials,iocharset=utf8,sec=ntlm,vers=3.0 0 0

So it seems it only works now if you bypass SMB1 and use other specified one, SMB3 worked for me so I haven't tried anything else.

I've used a local account on the windows machine not one with outlook.com domain name as I've read something that this could cause conflicts too.