CZ 3391 then 9C 7511 at Guangzhou
Zhengzhou → Guangzhou → Ningbo
Timetable, Guangzhou time
12:30CZ 3391 from Zhengzhou at the gate
11:409C 7511 to Ningbo leaves the gate
23 h 10 apart on the timetable, overnight
9C 7511 leaves 23 h 10 after CZ 3391 arrives on the timetable: more than half a day, so not a connection we count.