Flying without GPS using PX4FLOW

Dear community, sadly I could not find any sufficient answer searching the forum.

If I send the takeoff command using SITL (iris optical flow model, make px4_sitl gazebo_iris_opt_flow), failsafe is enabled:

simulator-oerlikon_1 | WARN [commander] Failsafe enabled: no local position
simulator-oerlikon_1 | INFO [commander] Failsafe mode activated

my non default parameter settings are:

COM_RCL_EXCEPT = 4
EKF2_AID_MASK = 2
EKF2_HGT_MODE = 2
EKF2_GPS_CHECK = 0
COM_POS_FS_DELAY = 99
COM_HOME_IN_AIR = 1
LPE_FUSION = 194

Does anybody have an idea regarding this error, I use 1.13 -stable

Regards