Trouble in paradise with Victron

[Surf City]

Hi folks

Went to charge batteries today and the Victron Multiplus 12/3000/120 started to give me a code of "the ripple voltage on the battery terminal is to high". I've check all terminals to battery and all clean. Have large enough cable size running to bus bars to batteries. Not sure where to start the process. I change the line voltage breaker to no avail. Power is getting to battery charger but as soon as I turn on to charge batteries the code pops up.

Please help with ideas. Have two kids who like to use electronics devices.

Wil