I've upgraded from a multiplus compact which performed flawlessly, but it was too under powered for my needs. I now have a problem with the multiplus II 12/3000/120-50 2x 120. When a RJ45 cable is connected to either VE. Bus connectors on the multiplus, I cannot turn on the Multiplus II either remotely or from the rocker switch. After disconnecting both cables, the RJ45 connectors from the Digital Multi-control and/or the Cerbo GX, the inverter will turn on. Once started, the offending cables can be reconnected. The inverter is connected to both the Digital Multi-control and the Cerbo GX and will perform normally. But if turned off either remotely or locally, the inverter cannot be restarted unless both cables are unplugged. I've tried using Victron certified cables, but that failed to correct the problems. I've seen several post that are similar, but none of these had a solution. Does this sound like a firmware issue?
