A clivia can stand in pleasant conditions during the afternoon and experience a much colder position beside the same window at night. Check the plant's location across the day, particularly where leaves touch glass or curtains enclose the pot.
Identify the plant and compare its requirements with the conditions you can provide. A warm room seen from the doorway does not tell you the temperature at the leaves.
Keep moisture in the picture
As growth and conditions change, check the compost before watering. A cooler root ball may dry differently from one in the same room beside a heat source.
Do not move the pot repeatedly in an attempt to manufacture a flowering response. Make a suitable arrangement, record the position and watch the plant's condition.
If leaves become damaged, photograph where the marks occur and note recent cold exposure or watering. Inspect for other causes rather than treating every winter problem as a lack of food. Flowers depend on the plant's overall growing history. A new fertiliser cannot undo damaged tissue or make an unsuitable night-time position suitable.
The RHS clivia guide describes a cooler, drier winter period, not exposure to frost. Its houseplant advice also warns that the space behind closed curtains can become very cold. Assess the leaves’ night-time position as well as the room.
Related reading: Clivia Winter Care: Light, Temperature and Watering.