Challenge Friend button is missing

Hi!
I’m having a strange issue, that happens both on PC, and on my mobile client (iOS with latest update, iPhone 11 Pro) - I cannot challenge a friend of mine, because the “challenge friend” button is missing. He can challenge me normally. Both of us have updated our games on all clientes, we both have “allow spectating” boxes ticked in and I have absolutely no clue why is this happening.

I have a screenshot, but cannot post it here.

EDIT - problem resolved, my friend needed to change his status in the BN client xD