Disk 1 Fail

I have a MyCloud Mirror 4TB unit, disk 1 failed (red light flashing) and now I cannot access my information, what are the next steps from best to worst case scenario? Thank you!

Hello puriarte, welcome to the WD Community. Sorry to hear you had problems with the drive. Follow the steps on the link below to restore your drive. 

Replacing an internal drive on a WD My Cloud Mirror, EX2, or EX4 Personal Cloud drive