Q.I Had A Healthy Creeping Vine On A Wall Of My House But Now The Leaves Are Falling Off Bottom Half. How Do Fix It?
Infested with black ants but can’t see any other pest. Not sure about drainage and there was consistent downpour about three weeks ago (root rot). Soil seems moist.

Certified GKH Gardening Expert
I would inspect very closely. Check undersides of leaves, or on dying leaves. This looks quite a bit like aphid damage, whether it be non woolly, or a woolly species. I do see some conserning white spots, and maybe a woolly aphid on one or two of the leaves. Ants will farm them for the honeydew that they excrete.
I'd treat for aphids and ants, and watch for the decline to slow or stop.
https://www.gardeningknowhow.com/plant-problems/pests/insects/homemade-aphid-control.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects/woolly-aphid-control.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects/controlling-aphids-and-ants.htm