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 temperatureRefitting the front wheel
When all the necessary inspections have been completed, refit the wheel as
follows.
Fit the spacers (3) and (9) to the seal rings on the sides of the wheel hub.
Install the complete wheel between the fork legs.
Lubricate the shank and thread of the wheel axle (10).
Take the pin ...
Refitting the expansion tank
If the support (15) has been removed, place the hose clamps (14) on the
bracket (15) orienting them as indicated.
Fully press the pins (a) to block the clamps (14) until pins surfaces (b) are at
the same level of the clamps (14) surfaces.
Apply recommended threadlocker to the thread of the ...
Reassembling the front footrest brackets
To reassemble the brackets (6) and (21) carry out the removal procedure in
the reverse order; tighten the screws (7) to a
torque of 25 nm +/- 10% (sect. 3 - 3, Frame torque settings).
...