I'd like to get an alert if a device is 'up', but Solarwinds has not been able to get data from it. (e.g. if an SNMP community string was changed or the SNMP engine crashed).
These guys get a little grey box in the node list:

But I can't figure out how to make an alert. I tried this:

but it doesn't go off.
How do I detect the things that have SNMP misconfigured?