Were all 3 boards showing the red LED on when it was having problems? If you want to rule out the IP issue, which I doubt it is, you can assign the antminer a static IP address.

Did you have a back-up pool assigned or only one pool? I wouldn't know what happens if the only pool on the list goes down, but if you dont have a backup, i would suggest a safe fall-back like slushpool or viabtc just in case.