After applying nvOC-19-2-update, one of the rigs probably doesn't boot to desktop cause VNC doesn't work, can access it by SSH or nvOC web interface:

nvOC v0019-2.0 - Community Release

Worker : 230

Boot Time: 2017-12-15 21:33:03
System Up Time: up 47 minutes
Miner Up Time: 00:00
Distro: Ubuntu 16.04.3 LTS 4.4.0-97-generic
CPU: Intel(R) Pentium(R) CPU G4600 @ 3.60GHz
Disk / Free Disk: 14G / 4.1G
Memory / Free Memory: 3917 / 3558
Load Average: 0.00 0.00 0.00
Nvidia Driver Version:
Reboot Required: No
Auto Temp Control: Enabled, Not Running
Watch Dog: Enabled, Not Running
Gpu Count:
GPU Target Temp: 65
GPU Minimum Fan Speed: 30
GPU Utilization: NVIDIA-SMI has failed because it couldn't communicate with the NVIDIA driver. Make sure that the latest NVIDIA driver is installed and running.
Currently Mining: BTG
Auto Switcher: WTM Profit Check Running.
BTC PRICE: 17729 USD
WTM Current Profitabilty: BTG:103 % ETH:100 % ZEN:82 % ZEC:81 % FTC:60 %
WTM Current Revenue: BTG:13.67 ETH:13.24 ZEN:10.81 ZEC:10.69 FTC:7.98
Miner Hash Rate / Output:

GPU Temp, Fan and Power Info:

GPU Temp, Fan and Power Alerts:

Watch Dog Alerts:


How can I fix Nvidia driver?