DL 706 then UA 516 at Atlanta
Denver → Atlanta → Chicago O'Hare
Timetable, Atlanta time
18:01DL 706 from Denver at the gate
15:32UA 516 to Chicago O'Hare leaves the gate
21 h 31 apart on the timetable, overnight
UA 516 leaves 21 h 31 after DL 706 arrives on the timetable: more than half a day, so not a connection we count.