Why is Kalshi not letting me combo?
Cause: the event isn't combo-eligible yet. Kalshi offers combos across many event types, sports and entertainment included, but only on events it has switched on. Eligible events are added on a rolling basis and typically appear closer to the event start time.
Fix: open the combo builder's own list of eligible events. You reach the builder from the page of any eligible event, or from the live tab by picking the sports category and then the combo builder. If your market isn't listed, it can't go into a basket yet; check back nearer the start.
Why does Kalshi say "invalid combo"?
Cause: a leg is no longer open. If any market in the basket has closed or stopped accepting orders, the combo can't be priced. Kalshi's help page doesn't use the words "invalid combo", but this and the eligibility timing above are the two causes it gives for a basket that won't build or price.
Fix: remove the closed leg, or replace it with an open market on the same game. Every leg must still be trading when you submit.
Why does my Kalshi combo say "payout unavailable"?
Cause: no one is quoting that exact combination right now. Combo prices aren't calculated from your legs; they come from a live Request For Quote, so a combo only shows a payout when a participant is willing to quote it. Longer or more complex baskets attract fewer quoters, as do quiet markets and combos built well before the event starts.
Fix: try a shorter or more common combination to confirm quotes are loading, and come back closer to the event start, when quoting activity concentrates. Treat it as a liquidity signal: a basket only one participant will price is one to price conservatively.
Why won't my Kalshi combo load a quote at all?
Cause: a weak or unstable connection can stop live quotes from loading on your phone or computer.
Fix: fully close and reopen the app, or refresh the page on web; log out and back in to re-establish the live connection; then build a different combo to confirm quotes are coming through.
Why didn't my combo order fill?
Fills are not guaranteed. If no participant answers the quote request, the order simply doesn't fill. And once a combo does fill, it can't be cancelled or reversed, so grade the quote before you accept it: multiply the leg prices for fair value in the free Combo Edge Builder and compare.
Combo settled for less than $1?
That's not a fault either. A blue arrow on a leg means it settled scalar, between $0 and $1, and the combo pays the product of every leg's value. See what the blue arrow means on Kalshi, and how Kalshi combos work for the full rule set.
Primary source: Kalshi's own troubleshooting and combo rules, Kalshi Help Center: Combos (read 2026-10-12).