Bad fridge smells are 90% from old food, spilled liquids in drain pan or crisper drawers. Deep cleaning + airing for an hour usually solves it.
See if any of these signs match your device — each one increases the likelihood of this fault.
These are the causes we encounter while repairing Bad smell from refrigerator — ranked from most to least common.
Old or rotten food
Spilled liquids in drain pan
Dead carbon filter (modern models)
Bacteria in drain tray under freezer
Dirty door gasket with mold
Clogged defrost drain
Any of the following = a danger signal — call now and don't try to fix it yourself.
On-site diagnosis, clear pricing before any work, and a documented 6-month warranty.