The condensation is probably caused by high humidity in the room and inadequate ventilation around the glass surface. Try the following:
Check that the room has adequate ventilation. If the room/window has an intake air valve, make sure that it is open.
The ideal relative humidity for indoor spaces is 35–55%.
Check that the room temperature is in the normal range (20–22°C).
Check that ventilation in front of the window is not blocked by curtains, houseplants, etc.
In a fixed window, it is common in certain conditions to have condensation especially around the edges of the glass and at the bottom. It is caused by a cold bridge that forms in the parting strips of the glass unit, which creates a cold zone in the window edges. It is also possible even if the thermal insulation capacity of the glass itself is above average. The condensation on the edges can even freeze in winter during very cold weather.
Especially in stone houses, internal humidity is higher than normal during the first few heating months, as humidity escapes the structure.
If condensation accumulates in a fixed window, it is especially important to maintain adequate room ventilation, correct humidity levels and ventilation around the internal surface of the glass.