If one of the fans has failed (inner and underneath) then the unit will just not quite get to temp, usually will sit about 8-12oC. So check both fans. With faulty inner you also may see ice built up on rear wall.
If fan needed;
Inner is SK135-FAN-INNER, $119
Under is SK135-FAN-UNDER, $89
Fill out form under to start process.

*Check your condenser under unit to make sure it hasn't bocked up with dust and particles. This is the part is a big black wire cage, and it's important to be clean.
*Is door sealing properly? A gap in sealing can cause unit to ice up on rear wall and stop air flow, causing it to not quite cool

Parts
Inner fan part number is SK135-FAN-INNER, $119, contact below to arrange
Under fan part number is SK135-FAN-UNDER, $89, contact below to arrange