Opponent Settings: Max Grid Size 16, Max Human Opponents 15, Fill IA Opponents OFF

After creating the session the online lobby shows 1/16 Driver Roster. Then I go to invite my friends and on the bottom right shows 0/8, I check one friend so 1/8, another one 2/8 and so on, when It reaches 8/8 thatīs it. No more players.

Why? Should be 16 and not 8.

My friends doing the same have no problems, they can reach 15 opponents.

Any clue?