the inverter stops working Multiplus C 12/1600/70-16

I have a problem with the Power assist function of the Multiplus C 12/1600/70-16 and briefly describe the problem.

When the Multiplus is switched on with a 230v mains, the inverter and the power assist function are switched on correctly but switch off after approx. 10 seconds. In fact, after a few seconds from the start-up, even in the presence of a load on the Multilpus higher than the set current limit, the inverter stops working, there is no more current withdrawal from the battery, and the LEDs of the Multi control of the inverter turn off and those of the battery charger light up.

All other functions of the Multiplus respond positively and in the absence of a 230v mains the inverter works normally.

However, the power assist works with the charger, i.e. the power of the charger is a function of the current limit set by the Multi control.

So in practice, the problem occurs when there is 230v mains current, the inverter operation is disconnected and the Power assist does not work.

Are there any settings that govern this operation?

Thanks in advance to those who can help me.