This would generally suggest the fridge is not cold enough, have you recently left the door open in error or defrosted it?
Yes all three flash to signify a fault, normally the operational temperature is out of an acceptable range.
Do both fridge and freezer compartments feel they are at the right temp?
It sounds like this is a PCB fault, where the control board isnt able to read the temperature correctly.
Should you wish me to suggest a local engineer to attend please provide your postcode, a new control board is around £100