No charge from shore power.

[SV Arcadia]

Hello all,

I recently purchased a boat equipped with 4 Optima lead batteries (one isolated for engine starting).
The batteries are maintained by a Marinco ChargerPro 30amp.

The batteries have worked fine for the first few months, however, one day, I came to the boat to dead batteries, most likely from the bilge pump, despite being connected to shore power and the charger indicating normal operation.

I am also able to use the electrical equipment with the engine driven generator and somewhat charge the now toast batteries but nothing from shore power.
Any tips on what I should look at before I replace the batteries?

Thanks