Unplug the Smile-T (square white box near the boiler) from the socket. Then click Anna away from the mounting part on the wall, check the wires, and place Anna back (click). Also check whether the Smile-T is properly connected to Anna. Then plug the Smile-T back into the wall socket and wait until Anna has started up.
Does the display still show "Loading please wait"? Then try to reset the Smile-T. This will erase all data except the WiFi settings. To do this, press the black button on the Smile-T for 15 seconds. After 15 seconds the LED lights will flash slightly differently and you can release the button. Wait for the Smile-T to finish resetting.
Then reset the settings in Anna, create a schedule, and add Anna to the app again.