Nvidia Sync failed with Unexpected Error ssh: handshake failed: ssh: unable to authenticate, attempted methods [none publickey], no supported method

Accelerated Computing DGX Spark / GB10 User Forum DGX Spark / GB10
1

Hi Nvidia team,

I have use Nvidia sync to connect my spark to Windows for 2 weeks.

but today is show error as:
**
Unexpected Error**

ssh: handshake failed: ssh: unable to authenticate, attempted methods [none publickey], no supported methods remain

I created another user, that works. I also tried to make ~/.ssh same as both user. but my main user still not working for Nvidia sync.

how to do this?

2

I am able to ssh user@gx10-xxxx via my windows

3

Can you share your .ssh/config file on your Windows machine? You should have an Include line and a host section for the Spark unit
Example:

Include "C:\Users\<Windows_user>\AppData\Local\NVIDIA Corporation\Sync\config\ssh_config"
Host sync-<spark_hostname_or_ip>
        Hostname <spark_hostname_or_ip>
        Port 22
        User <spark_user>
        IdentityFile "C:\\Users\\<Windows_user>\\AppData\\Local\\NVIDIA Corporation\\Sync\\config\\nvsync.key"
4

HI, here is my .ssh/config

Include “C:\Users\Andy Chen\AppData\Local\NVIDIA Corporation\Sync\config\ssh_config”

Host github.com
HostName github.com
User git
IdentityFile ~/.ssh/id_ed25519
AddKeysToAgent yes

5

I found those log in nvsync.log
{“level”:“warn”,“pid”:3840,“error”:“ssh: handshake failed: ssh: unable to authenticate, attempted methods [none publickey], no supported methods remain”,“alias”:“gx10”,“time”:“2026-07-08T12:51:41-03:00”,“message”:“cannot remove authorized_key”}
{“level”:“info”,“pid”:16388,“host”:{“name”:“gx10-ad7e\ SSH._ssh._tcp.local.”,“hostname”:“gx10-ad7e.local”,“ipv4”:“”,“ipv6”:“fd41:a0c:42d:1:3c9e:7fbb:2388:9680”,“port”:22,“info”:},“time”:“2026-07-08T12:51:55-03:00”,“message”:“Discovered SSH host”}
{“level”:“info”,“pid”:11084,“host”:{“name”:“gx10-ad7e\ SSH._ssh._tcp.local.”,“hostname”:“gx10-ad7e.local”,“ipv4”:“”,“ipv6”:“fd41:a0c:42d:1:3c9e:7fbb:2388:9680”,“port”:22,“info”:},“time”:“2026-07-08T12:51:55-03:00”,“message”:“Discovered SSH host”}
{“level”:“info”,“pid”:33884,“host”:{“name”:“gx10-ad7e\ SSH._ssh._tcp.local.”,“hostname”:“gx10-ad7e.local”,“ipv4”:“192.168.6.41”,“ipv6”:“fd41:a0c:42d:1:3c9e:7fbb:2388:9680”,“port”:22,“info”:},“time”:“2026-07-08T12:51:58-03:00”,“message”:“Discovered SSH host”}
{“level”:“info”,“pid”:32680,“host”:{“name”:“gx10-ad7e\ SSH._ssh._tcp.local.”,“hostname”:“gx10-ad7e.local”,“ipv4”:“”,“ipv6”:“fd41:a0c:42d:1:3c9e:7fbb:2388:9680”,“port”:22,“info”:},“time”:“2026-07-08T12:52:05-03:00”,“message”:“Discovered SSH host”}
{“level”:“info”,“pid”:16040,“host”:“gx10-ad7e.local:22”,“time”:“2026-07-08T12:52:08-03:00”,“message”:“Added host to known_hosts”}
{“level”:“info”,“pid”:10416,“i”:1,“hostname”:“gx10”,“time”:“2026-07-08T12:52:11-03:00”,“message”:“socket file exists, checking daemon status”}
{“level”:“info”,“pid”:34228,“alias”:“gx10”,“time”:“2026-07-08T12:52:11-03:00”,“message”:“Dialing remote machine”}
{“level”:“error”,“pid”:34228,“error”:“ssh: handshake failed: ssh: unable to authenticate, attempted methods [none publickey], no supported methods remain”,“time”:“2026-07-08T12:52:11-03:00”,“message”:“Could not create new SSH connection to gx10-ad7e.local:22”}

6

Can you make sure you have an nvsync.key in the location I shared earlier? If not, you may want to try reinstalling NV Sync

7

Hi, thanks for response.

Issue solved, my agent might accidently change ownership of user root folder. so ssh with ssh key stop working.