This is due to the base unit losing power and needs the clock resetting.
The handsets retain their clocks under battery power so this is a little misleading.

To reset the base unit clock:
- press the OK key
- press the 'down' arrow twice until "DATE/TIME" is displayed.
- press the OK key again, this will display the year. Enter the correct year on the handset numeric keypad and then press OK. (Only the last two digits of the year need to be entered).
- The date is then displayed in MM/YY format, enter the correct date on the handset numeric keypad and then press OK.
- The time is then displayed, enter rhe correct time on the handset numeric keypad and press OK.
- The handset then beeps and displays "SAVED".
- Press the "C" button and replace the handset on the base unit.

The base unit should now stop flashing "CL".

Re set date and time on main hand set