Multiecuscan

hi
i need help for connect my cantiecar to ducato 2012 for alignement

when i connect my cantiecar to ducato 250fl , message error :

error cantiecar/ ecu connection failled
can bus error, check if interface is properly connected to the vehicule and correct vehicule/module selected


i try connect with other vehicul, i selected 500xl , and connecting is ok , but error :
iso invalide
iso identified as body computer MM250fl

but when i selected good body 250fl connecting isn't possible


i don't no solution , can help me ?

thank you