Nvidia-settings in ssh. Failed to connect to Mir:

Hello friends.
I have Ubuntu 16 with several 1080 ti.
Connecting in ssh. to control fans i used
DISPLAY=:0 XAUTHORITY=/var/run/lightdm/root/:0 nvidia-settings -a [gpu:0]/GPUFanControlState=1
DISPLAY=:0 XAUTHORITY=/var/run/lightdm/root/:0 nvidia-settings -a [fan:0]/GPUTargetFanSpeed=80
All works fine!

But today my computer turned off because of electric power.
And now, after boot i have error when using this commands

DISPLAY=:0 XAUTHORITY=/var/run/lightdm/root/:0 nvidia-settings -a [gpu:0]/GPUFanControlState=1
Failed to connect to Mir: Failed to connect to server socket: No such file or directory
Unable to init server: Could not connect: Connection refused
ERROR: The control display is undefined; please run nvidia-settings --help for usage

What can happened?

Please check if there’s an Xserver running at all
ps aux |grep X

Thanks for reply!

user@comp:~$ ps aux |grep X
user 1902 0.0 0.0 21292 920 pts/0 S+ 21:38 0:00 grep --color=auto X

Obviously, no Xserver running that nvidia-settings could connect to.
Already rebooted?
Please run nvidia-bug-report.sh as root and attach the resulting nvidia-bug-report.log.gz file to your post. You will have to rename the file ending to something else since the forum software doesn’t accept .gz files (nifty!).

nvidia-bug-report_pt1.log (2.7 MB) nvidia-bug-report_pt2.log (3.2 MB)
I splited log in to 2 parts.
Also i made many reboots and no result…

There’s something wrong with one of the gpus, the driver loads but the underlying pci bridge is spilling errors:

[   83.690579] pcieport 0000:00:1c.7: AER: Corrected error received: id=00e7
[   83.690589] pcieport 0000:00:1c.7: PCIe Bus Error: severity=Corrected, type=Physical Layer, id=00e7(Receiver ID)
[   83.742375] pcieport 0000:00:1c.7:   device [8086:a297] error status/mask=00000001/00002000
[   83.791138] pcieport 0000:00:1c.7:    [ 0] Receiver Error         (First)

and the Xserver is outright crashing.
The gpu connected to the bridge is pci id 09:00.0, locate it, remove it, check if the system then works. Afterwards, plug it back in, maybe it’s just a bad slot connection.