Can't buy a player to a friend ?

[Romain Richard]

Hello all,
I'm level 6 at top eleven and my friend lvl 11
I want to buy him a player for my team but it doesnt work.
can you explain me why ?

I'm not english sorry for my poor english.

Thanks

[influenze]

You can only buy 3*, 4*, 5* players by negotiations and he need to be on the same server.