There is condensation on the inside of the cooker door
1.
It is normal for steam and condensation to build up in the oven during and after cooking, especially food with a high water content (e.g., frozen chips or chicken).
2.
To minimise steam and condensation being produced, avoid leaving food in the oven to cool down after being cooked.
3.
Pre-heating the oven before placing the food into the oven can help reduce the amount of condensation being produced