@AnnikaOsborne assuming nothing else has changed then it sounds like you are suffering from interference from other networks. In many situations it is impossible to find a wifi channel that is free from interference but try restarting your hub as that will make it find the least congested channel.
As everyone uses more WiFi and fit more wirless kit this problem is getting worse as the available bands get more congested. Systems like Sky's WiFi Max bundle can help as they use technology to minimise thecaffects. You can buy third party Whole Home WiFi systems if you prefer.
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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
