Error-trading-fractional-shares-on-Alpaca

I am attempting to run a strategy that trades fractional shares on Alpaca. I've configured the strategy to use "Market Open next Bar", and defined the "Qty Decimals" for the symbols in the "Markets and Symbols" window. However, when the strategy attempts to place a limit buy, I get the following error:

QUOTE:
"Alpaca" "Error placing trade: fractional orders must be DAY market orders" "fractional orders must be DAY market orders"

Hopefully this isn't some sort of general limitation on Alpaca where we can only use market orders?