UR5 Dual robot calibration no pop-up free-drive mode

Hello,
I have some troubles calibrating two ur5. When I follow the procedure for dual calibration, once I have mounted the calibration tool connector on the master robot’s flange and clicked on the proceed button in the first pop-up window, the second arm should enter free-drive mode so I could connect the second flange manually, and another pop-up should appear. Unfortunately I don’t get this pop-up nor the free-drive mode.

The only thing I see which differs from the procedure is that in the State Status window, one of the robots isn’t in idle mode but resetting when they should both be idle
Even if I switch the roles, the same robot is resetting :
Case 1 : Robot A master/Robot B slave ==> This robot Resetting
Case 2 : Robot A slave/Robot B master ==> Second robot Resetting

The two controller boxes have CB3.1 motherboards, with 3.15.8 software version. I set security to the lowest on the two robots
Would you have any idea why I don’t get the pop-up ? Is there a security parameter I missed which prevents me from doing the calibration ?

I found the problem. The robot with the resetting message was in reduced mode. By switching the robot to normal mode, the calibration went smoothly. Hope it will help others