Help with adding friend to 1v1 arena match

[Ultim1]

I'm new to the arena part of Blade and Soul.  Was trying to add my friend to an arena 1v1 match so we could trade wins to get the +70 def bonus.  Tried both private and public versions but both times when my friend tried to join it would say that they didn't meet the requirements to do so.  We're both level 19.  He's a FM and I'm a BM if that matters.

 

We did get sparring to work but it didn't count towards the achievement.  Just curious what we're missing to make this work.  Thanks in advance.