Here it is ! The Novation’s answer :
"Thank you for reaching out to Novation Technical Support, and thank you for your patience in awaiting our response, we are more than happy to help.
Only data from the controls and keys on the Launchkey itself are sent through the 5-pin MIDI OUT. It is not possible to use the Launchkey as a MIDI interface between your computer and ASR-10.
To be clear, the first port and the second output ports of the Launchkey are only used to allow the DAW to interact with the Launchkey itself, and not any external gear connected tot he 5-pin MIDI OUT.
Let us know if you have any questions or see any further issues. We’ll be more than happy to assist you.
AJF // Novation Technical Support Engineer"
I know its not really the subject of this forum post, but I post it there in case of someone like me, pulling his hair, with the same problem, comes here after been searching for “inactive port” on Google…
And it confirms that the statut column in Cubase doesn’t really mean something important in that kind of problem. “Inactive” port still works anyway actually. If not, the problem comes from another point as you can see.