Why can’t I create a challenge ?

Common blockers: not logged in; account banned; missing gamertag for that platform; balance below stake (remember Bo3 = stake ×3, Bo5 ×5); stake outside min/max (default $1–$500); trying a friendly ($0) match without a paid Silver/Gold plan or while friendlies are disabled; too many pending challenges (max 3 open, or 2 pending directs to the same opponent).