RPC Error with Remote WMI Calls

On some of my servers, I am unable to make WMI calls remotely, even know the service is running and the firewall rules are there.

When running something like:

Get-WmiObject Win32_UTCTime -ComputerName ...

I get:

Get-WmiObject : The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)

The problem was caused by an invalid reverse DNS entry. After deleting the entry I no longer have this issue.

After digging into this with wireshark, I found that I was getting RPC error packets that contained KRB5KRB_AP_ERR_MODIFIED. According to http://nwsmith.blogspot.com/2007/08/wmi-and-permission-denied.html this is indicative of DNS errors.