I've run into routers with out of date firmware that do that.
My advice is to update the router firmware.
I've noticed that when my husband comes home and his kindle fire and phone try to connect to our internet, we lose our connection. I have to then reboot the router and modem. I thought I was imagining it, but I had him turn off his phone and the internet connected. Is there something I can do for this? Do I need something to boost signal?

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