If the wifi LED on your Connected Indoor unit is flashing it means that there are problems connecting to the WiFi: WiFi on the EASYKIT Wifi With Netatmo is enabled but is not connected to your WiFi network
Check that your modem is powered.
Someone have changed an access password on your home WiFi network?
See FAQ "How can I re-set the WiFi network on my EASYKIT Wifi With Netatmo?"