Some cookers have doors that can be removed for cleaning.
The door hinges are often sprung to counterbalance the weight of the open door.
There is often a catch that will prevent the sprung hinge from disappearing inside the cooker when the door is emooved.
This catch on one or other hinge may have been disturbed (eg while cleaning)
Check the manual and see if your oven is equipped thus and how to release the hinge.
PS Be very careful as retrieving a hinge that has sprung inside IS possible but a pain in the alimentary canal