Why aren’t my orders filling in OnDemand or PaperMoney simulation trading mode?

This happens sometimes, because it's a free feature and therefore doesn't get priority tech attention the way Thinkorswim's live trading system does. But to help you troubleshoot, we've found that these are the usual suspects:

1. Thinkorswim's simulation trading system is down - call TOS support to verify
2. There's a glitch with your particular ticker, so try a different one instead (i.e. QQQ instead of SPY)
3. Your limit price is set too low/high
4. The market isn’t open (open hours are 9:30am-4pm Eastern Time Mon - Fri)