NSM devices disappeared from update device list
You're right , it shows down , and some shows "..."
So your all the devices are showing down which mean NSM device server is DOWN, can you check in Administer > Server Monitor (Check for device Server).
If it is down, then check the devSvr status from CLI: service devSvr status (if it is off, start it)
in status it shows ok
any way I restarted it , and also rebooted the NSM device ..
still showing "down"
The problem has been solved ..
It was relted to our last backup .. we forgot to remove the RSA keys from the devSvr.cfg
now the staus shows ok 🙂
Yes, I was about say the same thing once I confirm about device server down.
This is mentioned in Kb article: https://kb.juniper.net/InfoCenter/index?page=content&id=KB11016