At the open order could not be executed

Hi,
Have anyone ever encountered “At the open order can not be executed” for an order to exit an existing position at OPG/MKT.
This happened to me today in a paper trading mode. The order was placed few hours before market open and the cancel message above was received 31 seconds after market open. Other OPG/MKT that I placed at the same time were filled 2-3 seconds after open.
Is this something that can happen in live?
Thanks, N

 

What product? Stock, options, futures? How did you route the order, direct, smart?

 

From my experience OPG orders don’t work in paper mode

 

IB paper trading does not simulate MKT OPG orders properly.

I've never had a live MKT OPG trade not fill (unless it's a buy order and there's insufficient buying power).

 

It is a stock which is routed via SMART