The activation of this (amber yellow) "warning" indicates that the hands free system has detected that the battery that permits the active key (1, fig. 62) To communicate and turn the vehicle on is almost discharged.
Note
In this case, ducati recommends replacing the battery as soon as possible as described in the paragraph "replacing the active key battery" (page 88).

Hands free key (hf) not recognised
High engine coolant temperaturePassive key
Introduction
The passive key (1) is used when the active key is not working correctly or
is not available.
The passive key works as a transponder, and must therefore be placed physically
onto the antenna to work.
The mechanical part (2) of the key is used to open the seat or the tank plug ...
Renewal of the cooling fan
Loosen the electro-fan retaining screws (15) and (17) and remove the
electro-fan (18) from the radiator.
Carry out the same procedure for the other radiator's electro-fan.
On refitting, position the coolant radiator fan (18) as shown on the fan support
(16), so that the three fan holes mat ...
Storing the bike away
If the motorcycle is to be left unridden over long periods, it is
advisable to carry out the following operations before storing
it away:
clean the motorcycle;
empty the fuel tank;
pour a few drops of engine oil into the cylinders through the
spark plug bores, then turn the engine over by hand ...