VE.Direct port
These are not common and if this occurs it is probably due to one of these issues listed in this paragraph.
Physical cable connector or data port issues Try a different VE.Direct cable and see if the Multi RS will now communicate. Is the connector inserted properly and deep enough? Is the connector damaged? Inspect the VE.Direct port, are there bent pins? If this is the case, use long nose pliers to straighten the pins, while the unit is unpowered.
Note, unlike most other Victron products it is not possible to connect the Multi RS to a GX device (i.e. Cerbo GX) using the VE.Direct interface. You must use the VE.Can interface to connect to a GX device.