WotLK Can't create 2s team on Blackrock - "level is too high"

[Broodyr]

I've been trying to create an arena team with my friend on Blackrock, but every time we try (either direction), we get the error "XXX's level is too high to join your team". We're both obviously level 80, so what's the problem?

[Broodyr]

Nevermind, found out it was because he was unknowingly on the progressive mode. Just had to get him to change the setting with the NPC.