Error #67 BMS Communication lost

I have an issue with a couple of units.
Both are coming up #67 BMS Communication lost.
Am using Pylontech US5000B batteries and Cerbo MK2.
Have used Old cerbo model prior to the MK2 with no issue.
Have tried;
DIP Switch
New Cable
Another MK2 Cerbo.
and calling supplier of batteries, still same issue.
No packets dropped under services
Battery is not in alarm state.
Could anyone shed some light on this?
Much Appreciated.

Do you have any communication with the US5000s at all? For example, do you have live data in the Device List?

Default CAN config for the Mk2 VE.Can 2 port (physically, same location as Mk1 BMS-CAN) was not 500kbps (might be in current firmware) so check that.

You shouldn’t need to change DIP switches on Pylons ever, unless you’re using more than 15 and an LV-Hub or something.

The pylon talks as normal but sporadically might just stop working.
could go a day or it might go 5 minutes.
Just strange on the 2x Cerbo MK2 systems.
i have it set to LV 500kbits.
I only changed the master “1” on the DIP Switch

The DIP switches should all be set to 0, see the Victron / Pylontech integration guide:

Important note on DIP switches

No adjustment to the DIP switches is necessary, unless you are using a LV-Hub to connect a large number of modules. The address DIP-switches must be set to 000 for correct operation, and the GX device will not detect the battery if you use any other setting. Larger batteries using an LV-Hub is discussed later in this document.

There is a fault in the software. I’m also having a Cerbo MK2 and before I had 3.5x the installation worked fine (correct setup with 500 kbits)

How do we go about rectifying the issue? I have customers that rely on their systems being functional as they are off-grid.
I sold them this Combo from my own personal experience and now they are failing.

In the Cerbo it’s possible to go back to previous versions (before v3.5)

Started at 3.5 on Cerbo, Installed 3.51 and now 3.52 still same problem

Not sure if that would support the software based input ve.can 2, as the cerbo MK2 doesnt have dedicated BMS input anymore.