@Lubylu " No host network connection" is an indicator that RE failed to connected to router's wifi.
Try verifying the wireless password on your smartphone to make sure it is the correct one. For example, forgetting your main Wi-Fi network, then connecting back and entering the same password you were giving the extender. There are cases where the smartphone capitalizes the first character which can cause issues.
You could try to troubleshoot as Case1 & Case2 in this topic:
https://community.tp-link.com/en/home/forum/topic/198516