You are correct, your converter or inverter/charger SHOULD charge the house bank when on shore power or generator (basically any source of 120 VAC). This assumes that there is no disconnect switch between your house bank and converter or inverter/charger that is in the off position. Some coaches have this switch, others wire the charging device direct to the battery.
SO, start by verifying that you do have 120 VAC to your charging device (BTW, let us know what it is-- converter or inverter/charger and model if you know it). Check breakers/fuses to it.