Market orders not filled

Hi everyone. My system calls for opening positions at marker, at open. I usually place my signals about 5 minutes before open. For the second day in a row, my opening signal (MKT, short, UDOW, well within margin) is “working” at 9:46am and 9:36am respectively, thus missing the window. I’ve submitted tickets with no answer. Is anyone having the same problem?

Have a good one,