AC 8256 then WS 2712 at Toronto Pearson
London (YXU) → Toronto → Cancún
Timetable, Toronto time
10:09AC 8256 from London (YXU) at the gate
09:25WS 2712 to Cancún leaves the gate
23 h 16 apart on the timetable, overnight
WS 2712 leaves 23 h 16 after AC 8256 arrives on the timetable: more than half a day, so not a connection we count.