my 8 years old indesit fridge makes a block of ice in the right lower corner at the back. Is this a sign that is time to change it? what is causing this problem? I have seen this happening in many old fridges. it is not just condensation since it only happens in a corner. It is not a clogged drain since the ice is vertical on not in the drain. It does not seem a broken thermostat and it also happen increasing the temperature.

THANK YOU SO MUCH!!!