Smart battery voltage low and smart bms 12/200 won’t turn on

New to me boat and looking for advice on how to restore power to the smart bms 12/200. Victron smart battery voltage is low and will not power up bms. System has two batteries connected in parallel and a Multiplus 12/2000/80 charger/inverter is connected to the bms. With main AC power supplied, the charger will function but only charge the engine cranking batteries. No charging current is being supplied to the smart lithium ion battery bank and no LED lights are illuminated on the bms.

Do I need to charge the smart lithium ion batteries separately before the system will restore power to the bms and allow the Multiplus to charge the bank?

The absolute first thing you should do, is to use Victron Connect and try to connect via bluetooth to your batteries.
You should be able to connect if the batteries are over about 8.5v.
Confirm battery voltage with a multimeter.

If the batteries are below 10v, they are broken beyond repair, and are no longer safe to use.

Read the Manual.