My Wifi works fine with my Laptop, but doesn't work with my Phone or Tablet?

I have a Surface Pro 3 and the wifi works fine with it. Relatively no problems whatsoever. But if me or my family tries to use any sort of mobile device, the internet connection is extremely poor, and rarely loads anything. We all have Samsung Galaxy S5's and a Galaxy Tab 4. I've tried resetting the router, factory resetting the router, deleting and redoing the information on the devices, and it still doesn't work. I tried googling it but nothing that shows up is even closely relevant to what I'm trying to find. Anyone have any suggestions?

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