I downgraded to Mission Planner 1.2.90 and it works !!
So it is not a SITL issue, it is a Mission Planner issue.
Looking at the new features of 1.3.28, there is a new SITL implementation embedded and not yet fully fonctionnal:
The SITL software in the loop simulation system has been completely
rewritten for this release. A major change is to make it possible to
run SITL on native windows without needing a Linux virtual
machine. There should be a release of MissionPlanner for Windows soon
which will make it easy to launch a SITL instance.
The SITL changes also include new backends, including the CRRCSim
flight simulator. This gives us a much wider range of aircraft we can
use for SITL. See dev.ardupilot.com/wiki/simulation-2/ for more
information.