Mycloud Ex 2 is making noise / Disk 1 flashing blue & turn off

hi,

I have a WD Red 3 TB NAS Hard Drive: 3.5 Inch, SATA III, 64 MB Cache - WD30EFRX (disk 1) and it is not working in my My Cloud EX2.When I power up the ex2 i hear a noise and disk 1 light is flashing blue then disapearing then flashing blue again. I wait and i'm hearing the same noise until the power button is turning yellow a couple seconds later (still a noise). the disk 2 is the same hard drive but with the red label on it. The other one don't have a red label, just plain indications with the WD logo. Disk 2 indicator stays blue. I tried to retrieve the disk 1 and leaving the disk 2 : no noise, everything is silent and the disk 2 indicator stays constant blue...What's wrong?Help please

up, please?