@SofiaBarbeitos modern phones will switch to use mobile data if the wifi connection is poor you can alter this by turning off a setting called WiFi Assist in mobile data settings on iPhones modt Android phones have a similar setting.
If WiFi signal is poor in your home check your hub is in the nest position which is out in the open on a surface so it is aboce obstructions like radiators. Otherwise you need to get extra Wi`Fi kit which Sky will provide if you buy their https://www.sky.com/help/articles/sky-wifi-max
Alternstively you can buy and use your own WiFi kit.
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65inch Sky Glass, 3 Sky Streaming Pucks, Sky Ultrafast + and Sky SR213(white Wifi Max hub) main Wifi from 3 TP-Link Deco M4 units in access point mode
