No logon servers Error 5719

For some reason I am getting the following on all my workstations:

Error ID 5719. Source Netlogon
No Domain Controller is available for domain <my domain name here> due to
the following:
There are currently no logon servers available to service the logon request.
..
Make sure that the computer is connected to the network and try again. If
the problem persists, please contact your domain administrator.
For more information, see Help and Support Center at
http://go.microsoft.com/fwlink/events.asp.

I have looked at everything I can think of.

I can login to the domain
I can ping the DC
The computer is in the DC
The DC is the DNS and is pointing to itself
I can see and use file/print shares, etc.

Basically, if I didn't look in the event log I probably would not see
anything wrong with the network except for one thing. I have one machine
that uses a share on another as a source of family pictures for a screen
saver. This is mapped as the T: drive. This will work fine for about a
day, and then when you look at the screensaver it will indicate it can no
longer see T:. I have to reboot to regain connectivity. I can still see
the other machine, but it won't reconnect on the fly. This is what started
it. Other than that everybody can login, print to network printers, see
each others shares, whatever. I have looked at numerous MS KB articles but
can't find an appropriate solution.

--
--Jim
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