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 temperatureRemoval of the front wheel
Support the bike so that the front wheel is raised from the ground.
Remove the front brake calliper (b) by unscrewing the two screws (a) securing
the calliper to the fork leg; do not
disconnect the calliper from the hose.
Warning
Do not operate the brake lever when the callipers are ...
Refitting the brake disks
Before refitting the brake disc to the wheel, clean all contact surfaces
thoroughly and smear a medium strength
threadlocker on the threads of retaining screws (5).
Operating on the left side, fit the phonic wheel (6).
Tighten the fixing screws (5) of the brake disk (7) to the wheel followi ...
Refitting the cooling system hoses and unions
Position the pump/radiator sleeve (22) and the radiator/radiator sleeve (23).
Fit sleeve (23) and sleeve (22) to their corresponding fittings (n) and (o), and
bring them fully home on collars (p).
Note
Sleeves (23) and (22) must be oriented so that the grooves (q) match the
tabs (r) on fitt ...