Problem with a 'fault' drive status and a red LED light

I noticed my enclosure had a red LED light on and then checked in the system and noticed there was a fault on of the drives. Do I need to replace it with a new hard drive or can it be repaired?

Red light can come on when the drive is 90-95% full.

If drive get overheated due to insufficient air roration on top of drive, Red Led may glow.
I moved unit to open air lication, it became normal…but I had to do factory reset everytime i shutdown unit…