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 temperatureInjection and ignition
Introduction
Ignition is via a single stick coil per cylinder installed in the spark plug
well. Each thermal unit is supplied by a single
injector, placed under the throttle valve. The amount of fuel injected and the
ignition advances are determined by the
control unit specifically for each c ...
Removal of the exhaust system
Remove the silencer, as described in the paragraph "removing the silencer" of
this section.
Loosen the screws (28) and remove the exhaust by-pass valve cover (27).
Turn the exhaust valve pulley (a) to facilitate the throttle cable (25)
output.
Release the end fitting (b) of the cable ...
Key-on/key-off using the red key on the handlebar with the passive key
A key-on can be performed by pressing the red button (6) on
the handlebar in the hands free on/off position and in
the presence of the passive key (4, fig. 77).
Note
The passive key (4, fig. 77) Has a range of a few cm,
therefore the key (4, fig. 77) Must be positioned near the
antenna (2). R ...