Hi,

 this status mean - hostname(s) not resolved during polling process.

As example, when your DNS server not respond, stopped working as an user written here.

Marios Palechoros via observium wrote on 27.10.2020 12:35:
Hello all,

I can see in my observium installation that many devices changed their status to down(dns).
This is a new installation and we migrated the configuration yesterday on a new server and devices were working properly.
At around the same time (14:20:00) a lot of our machines changed their status to down.
The message in the Event log is "Device status changed to Down (dns)". I tried to find what the problem may be but I can see SNMP are correct and dns records exist for the systems.
Any ideas?

Thank you,
Marios

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