I believe the random method my router uses to assign network addresses might be causing a conflict if I reboot my router and the address assigned to a folding PC changes while F@H is running.
I rebooted everything, the network conflict disappeared and everything started working again. The PC that caused the problem downloaded a new WU and started working on it.
I believe I can force the network address assignment that occurs by connecting the PCs to the router in a specific order, but I can't do that if the router reboot occurs when I'm not around. (Power failure.)
[22:31:43] Writing local files
[22:31:43] Completed 3240000 out of 4000000 steps (81)
[22:46:55] CoreStatus = 1 (1)
[22:46:55] Client-core communications error: ERROR 0x1
[22:46:55] Deleting current work unit & continuing...
[22:47:15] - Preparing to get new work unit...
[22:47:15] + Attempting to get work packet
[22:47:15] - Connecting to assignment server
[22:47:17] Couldn't send HTTP request to server (wininet)
[22:47:17] + Could not connect to Assignment Server
[22:47:17] Couldn't send HTTP request to server (wininet)
[22:47:17] + Could not connect to Assignment Server 2
[22:47:17] + Couldn't get work instructions.
[22:47:17] - Error: Attempt #1 to get work failed, and no other work to do.
Waiting before retry.
Did you try using a shorter cord?
Have you tried using static IPs?