-Check that the temperature around the fridge is 25 degrees or under.

-Check ventilation around the fridge. You need approximately 20mm at sides and top with 100mm at the rear.

-If the fridge is in a cupboard, you need to have ventilation which we call the chimney effect,  You need a vent for fresh air to come in from the bottom of the cupboard and a vent for hot air to escape from the top. 

 -Check inner fan is going and that there is NO ice build up on the inner rear wall

 -Check temperature gauge.  6 being the coldest