Why can't some people be challenged?

Question

Sometimes, when I go to the profile of someone to challenge them, the Challenge option is grayed out. Why is it so? Is there an option to set the minumum level of the challenge? Is there an option to block some people? Is there an option to make it so that only I can challenge others but others can't challenge me?

Answer 1

Those people must have disabled all the weapons for challenges from their settings, thus you can't challenge them until they enable a weapon. If they themselves start a challenge, the weapon gets enabled automatically.

Answer 2

hmm.... ok.