Deco Wifi network setup - Main Deco M9 Plus | Location - Garage 2 x M9 Plus | Location - Office & Walk-in Wardrobe M5 | Location - Shed Main Deco M9 plus is set up as a router / fast roaming disabled

My daughter's iPhone has stopped connecting to our Deco wifi. We have wiped the network setting on the phone which didn't work, we even completely reset to iPhone. The phones find the network but just