@MeMi If you are using the ZTE router as a modem for the Deco mesh did you remember to set it in modem only mode? If so then why not connect the Deco system in router mode? Or are you still using the ZTE wifi system as well?

  @MeMi I can't say why your homekit devices aren't connecting but my understanding is that you'll need to set at least one device up in router mode otherwise you'll have no DHCP server in place, so none of the devices will be assigned IP addresses which would explain why you have no internet connection in AP mode. I assume the homekit devices connect through some sort of hub so maybe try setting the Deco mesh up in router mode to get the internet back on and check to make sure that the IP of the homekit devices falls within the start and end range of the Deco DHCP server. You'll find this under the Advanced > DHCP Server settings in the Deco app. I'm not sure where you can check the IP on your homekit devices though, sorry!