I am running openHAB on a Raspberry Pi 3 and recently updated to the newest OH2.3 version. After rebooting I had the problem, that my “Z-Wave Serial Controller” was offline with the message:
Port /dev/ttyAMA0 does not exist
I am using the RaZberry daughter card that sits on top of the Raspberry PI GPIO connector.
RaZberry - z-wave.me
I was struggling a lot and after two days of research finally found the solution in this post:
OpenHAB won't recognise zwave dongle
The problem basically was, that the user openhab wasn´t included in the group dialout, to which the serial folder /dev/ttyAMA0 belongs to. I only had my local openhab-user included in this group and thought, that would be enough!
ls -al /dev/ttyAMA0
should show something like this:
crw-rw---- 1 root dialout 204, 64 Aug 6 23:09 /dev/ttyAMA0
No you can check, if your openhab user belongs to the group dialout by
getent group dialout
if it shows
dialout:x:20:someuser,openhab
you are good! openhab is included! If it is not, you can change that by typing
sudo usermod -a -G dialout openhab
Be careful to not forget the -G parameter, as otherwise the openhab user would be removed from all other groups and in the end will ONLY be in the dialout group! We don´t want that 
I just wanted to share this information with you, so you hopefully don´t have to spend two nights searching for this simple solution!