I am having a similar issue with Time synchronization fail as the user in the following thread.
Dec 09 09:28:58 WAN: WAN 4 Disconnected (Manual)
Dec 09 09:28:52 WAN: WAN 3 Disconnected (Manual)
Dec 09 09:28:39 WAN: WAN 2 Disconnected (Manual)
Dec 09 09:28:29 WAN: WAN 1 Disconnected (Manual)
Dec 09 07:31:30 System: Time synchronization fail
When this occurs I have to manually disconnect and reconnect all the WAN interfaces to get access to the Internet again.
I was running Firmware 6.1.1 on Balance 50. I have since updated the firmware to 6.1.2. Does anyone know if 6.1.2 fixes this issue? I am going to monitor it for now.