Air noise from door
Aristoclis,
If you still have reports of this noise after the door has been opened and cycled and checked for obvious seal damage. No catering debris under the door seal then this could well be the door 1R sill scuff plate.
Quick t/shooting and isolation is to apply aluminium high speed tape to the outer door sill. The scuff plate sealant may have de-bonded from the fuselage and is now causing high speed airflow to give that high pitch whistle - 'blowing across a coke bottle top'. Remeber to ask the crew to report back as this noise is a killer in cruise.
Fix will be eventually to remove the scuff plate and reseal with aerodynamic sealant. It is a fairly common fault that I have come across on both Boeing and Airbus aircraft.
TW