A leafy lantana is not necessarily short of food. Before changing fertiliser, look at the light reaching the plant and the growth you are asking it to support.
A shrub tucked behind other plants may have less exposure than it did earlier in the season. Check the actual position through the day rather than relying on how bright the garden looks from indoors.
Review the recent routine
Write down when the plant was fed and pruned. Repeated feeding and frequent trimming can complicate the picture; adding more of both gives you little information about the original problem.
Check the root area too. In a container, inspect drainage and moisture below the surface. An otherwise suitable position will not correct a pot that stays waterlogged.
Confirm the cultivar and whether the plant is actively growing in your local conditions. If nights have cooled or growth has slowed, do not expect the same response as in warm weather. Make a sensible correction, then judge new growth over time. A lack of flowers is not, by itself, evidence that the plant needs a stronger feed.
Related reading: Lantana Care: Growing Conditions, Feeding and Pruning.