DL 2709 then UA 2168 at Houston
Atlanta → Houston → Denver
Timetable, Houston time
13:23DL 2709 from Atlanta at the gate
12:45UA 2168 to Denver leaves the gate
23 h 22 apart on the timetable, overnight
UA 2168 leaves 23 h 22 after DL 2709 arrives on the timetable: more than half a day, so not a connection we count.