I started placing limit orders at 9:38am (about 8 minutes after open). I canceled them as it wasn't executing even though I was placing the limit orders at the bid. I placed the market order at 9:41 and canceled at 9:43 because it wasn't executing. I waited until I saw the stock moving again which was at 9:47. It executed as soon as I put the order in at that time, so for about 9 minutes my orders weren't executing. The rest of my trades/quotes were moving normally. It was only MRO that was weird.