Contact between an appliance and surrounding furniture can transmit vibration. The required clearances must still be taken from the model's installation instructions.
What the observation tells you
Do not push or pull a heavy refrigerator while it is running to see whether the noise changes. A trapped cable, delicate floor or integrated fixing can turn a simple observation into damage. The visible gap alone may not show contact elsewhere.
A useful next step
Note where the cabinet appears close to furniture and whether the sound began after room alterations. Ask for an access or installation assessment where appropriate rather than inserting packing or altering ventilation gaps yourself.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.