Cooling pump buzzing

Hello,

Here I am relying on the community's knowledge as I couldn't understand where the noise from my watercooling pump is coming from.

It is a buzzing/vibration: I filmed it so you can see what it's about.

https://www.youtube.com/watch?v=AhKCEFXDrLg&feature=youtu.be

It is an Enermax Liqmax 120

https://www.cdiscount.com/informatique/ventilation-refroidissement/enermax-liqmax-120/f-10789-elclm120shp.html

For your information, I tried tightening the fittings and unscrewing them as well. No way to make the noise stop.

Thank you for any answers you can provide.

Best regards
Thrallcss