Hi,
Sorry for the slow reply.
There seems to be the problem.
The CEC bus only supports a limited number of roles within the CEC bus, and only a limited number of devices can take each role. If this is correct, then disconnecting other peripherals from the TV / AVR should resolve the problem. I understand this isn’t a fix but it would be good to test that.
It might help to change the type of device that Vero 4K advertises itself as. See Vero2 CEC error message - #13 by makk509 for some more information.
The included cable is just a cheap and cheerful 1M cable to get people started if they don’t have a spare.
Cheers
Sam