De Dietrich fridge isn't cooling properly?

Our De Dietrich fridge / freezer has started flashing LF and LC on the LED display where there used to be temperatures.

The manual says this is a warning that the temps in both the fridge and freezer compartments are too high.

I set the temps for lower, which didn't work, then unlugged and plugged back in.

None of that has worked so far.

Any ideas please?