What does a warning icon on a conditional forwarder mean in Windows DNS Manager?

The icon for one of the conditional forwarders on an Active Directory DNS server I manage has a standard warning icon (yellow triangle with exclamation point) overlay (all names have been changed to protect the innocent):

I've scoured the included .chm documentation, sifted through the Technet docs with a fine-tooth comb, googled and googled until my fingertips got sore, but I haven't been able to find any explanation anywhere of what this means. Looking at the details pane of the properties yields no clues.

For the DHCP console, there's a handy icon reference, but I can't find anything similar for DNS Manager.

Here's some context, although I want to focus specifically on what this icon means, and whether there's an icon reference for DNS Manager.

A few days ago I added a couple of IP addresses to the Conditional Forwarders list for a particular domain (let's call it differentdomain.com) on several DNS servers in two other forests. (The conditional forwarders are configured per DNS server, not replicating through Active Directory).

Everything was working fine, but today one of the DNS servers on which I made the change is not resolving hostnames in differentdomain.com. For any hostname in that domain, nslookup throw the error

*** dc-with-adi-zone.companydomain.com can't find whateverhostname.differentdomain.com: Non-existent domain

None of the other DNS server on which I made the same change are having this problem, and they all have the exact same conditional forwarder configuration for differentdomain.com. The server that's having the problem has several other conditional forwarders configured, and there are no problems with any of them.

Solution 1:

That icons means something is wrong and nothing else. It's a generic indication of a problem and it's not meant to convey a specific error message. For that you should look at the event log and perform the usual investigation steps.

I checked the DHCP icons and, if they really mean what the documentation says, they are really misleading (e.g. a server with a "stop" overlay means the user doesn't have admin rights? Shouldn't it mean the server is stopped? My point is an icon cannot provide complete information unless the information range is really limited).

You should not rely on icons to get a complete picture of what is wrong. Do not obsess over the meaning of them. Event logs are much more reliable, comparatively, and the warning icon should be enough information for the system administrator to notice something is not right and start investigating.

I don't think the ServerFault community will be able to provide a specific answer, unless we've the Windows Network core development team here.