Give it a bit of time... herbicides such as 2,4-D don't work overnight.
Also, for your reference...
Herbicides like 2,4-D work best when there is maximum contact of the herbicide to the plant surface area.
For this reason, the ready-to-spray jugs with the motorized sprayer wand are helpful so you can spray the weeds from different angles.
Wear a mask, gloves, and long pants to stay safe. 2,4-D was in Agent Orange. (Opposition posters... save your breath; I am WELL AWARE that agent orange had another herbicide analogue as well as a dioxin by-product).
Good luck.