I can't figure out what I'm doing wrong with this StockTrak Bull Put Spread trade?

When I put it through, it says "Some orders are rejected" or "Instrument [WMT2016J75] price must be set". I have no idea what this means or what it wants.

I'm trying to bet on Walmart stock. I believe the stock will continue to rise. So what am I doing wrong here?

TRADE OPTIONS SPREADS PORTFOLIO LUC-FINC346-F20 Switch Exchange UNITED STATES SIMPLE SPREADS A This market is now closed. Market orders placed after-hours will be sent to the market at the open of the next business day. Action Quantity Stock Symbol Call/ Put Expiry Strike Buy to Open 15 WMT Call 10/16/2020 75 Action Quantity Stock Symbol Call / Put Expiry Strike Sell to Open 15 WMT Call 10/16/2020 80 Order Type Limit/Stop Price Order Term Date Market Price Good-til-Day mm/dd/yyyy Stock's Last Price Day's Change Bid Ask Day's Range Day's Volume 137.27 0.57 136.65 137.20 135.96 - 137.54 7,539,596