Invalid commission selection
Payout flow rejected the chosen commission ids (generated.invalidCommissions / Invalid commission selection.).
Why this happens
Selected commissions are missing, already paid/held, or not owned by this user. Distinct from Invalid commission selection for this amount (ids valid but totals do not match the requested amount).
Diagnose and fix
1. Refresh the payout UI; re-select currently withdrawable commissions.
2. Do not mix already-requested or still-held rows.
3. See Amount exceeds available affiliate earnings after pending holds if the balance is the real issue.
4. See Request a payout and Affiliate commissions ledger.