Hi, I currently have a Samsung Galaxy S4 and This issue has really frustrated me. I have looked everywhere looking for answers and having them connect my internet but not actually letting me use it.
1. Try changing it so static mode instead of DHCP ( When you first connect to the internet, you should have two tick boxes which say show password and Advanced settings, You want to tick them both and then scroll down to where it says DHCP. This needs to be changes to static. Then enter all of the gateways and ip addresses and this connects you to the internet. NOTE: only do this for this solution if it works for you.)
2.Do 10,10,10 ton your WIFI Router (Hold the reset button for 10 second, then without releasing the button unplug the router. Then again plug it in and immediately hold the button for another 10 seconds)
3. Where you would normally dial a number (Not from contacts) Type *#0011# and it should take you to your services. Then you want to go into options and into WIFI. Once you do that you need to make sure the WIFI Powersave is off. Then turn your WIFI off and the on again and it may solve the problem.
Let me know if any of this helped any of you