It is possible that due to circumstances, the indoor unit no longer receives the DCF signal.

You can try moving the indoor unit to another location and see if it receives the signal.

The DCF signal is transmitted 4 times a day at 2:00, 8:00, 14:00 and 20:00, and it is best to use the RCC button to switch on the DCF function at that time.

In extreme cases it can happen that the DCF time is only displayed after more than a day.