A decorative outer pot can hide a drainage problem. After rain, water may collect around the nursery container even though the inner pot has perfectly good holes.
Lift the inner pot and check the bottom of the cover. If it contains water, empty it and arrange the plant so drainage can escape rather than building up unnoticed.
Check the whole route out
A hole in a container does little good when it is pressed flat against a surface or blocked by compacted material. Check where the water goes after leaving the root ball, especially if the pot sits on a tiled balcony.
Peonies in containers still need moisture appropriate to their growth. Avoid solving standing water by withholding all water for an arbitrary period. Feel the compost around the roots and respond to its condition.
A cover pot with no outlet needs regular inspection outdoors. If you cannot check it after rain, use a different arrangement. The choice is practical: the plant should not depend on someone remembering that an attractive container is also collecting every shower.
Related reading: Peony Flower Care: Soil, Watering, Feeding and Light.