@KatsB Replace your Deco unit from Satellite Unit to Main Unit or change the ethernet port to port (2) and then check your speed.

@KatsB Your WAN port speed is 100 Mbps that's why Deco App showing Abnormal WAN Speed you have to change your ethernet cable maybe your ethernet cable is old / damaged or misconfigure that's why your...

@ryg Yeah because Web UI works locally without internet connection and Deco App work with internet connection.

@David-TP Again Deco App showing offline satellite units.

@SayeemAhmed Yeah because you force the device to always connect to 5 GHz so the device will only connect to 5 GHz not gonna connect on 2.4 GHz but to resolve this problem you can separate your SSID...

@cdsatp Main Deco connect with ISP's router by ethernet cable to get the internet connection from the ISP router and turn off the WiFi of your ISP router to access internet from Deco X20