A few months ago I got the Galaxy S4 from Vodafone and I have been having problems with it ever since, espcially the Wi-Fi connection.
When I connect to my Wi-Fi at home, it connected and nothing else happened. I was not able to load websites and do anything else that requires the internet. When I then disconnected and connected again, it worked. Really strange. So I had to get used to connecting to every network twice before I was able to do everything. And everytime when the phone dropped the connection (for example when I went outside), the same thing happened and I had to connect twice as well. At first I thought it is because of my Wi-Fi, so I went to several friends who all have a different router, but same thing here. I have looked through some forums of Samsung and found out that it might have something to do with the TKIP settings of the router. So I tried and changed that as well. But still, did not work.
Since yesterday there is Android 4.3 for the phone and it has gotten even worse now. Every time I connect to a Wi-Fi network, it does this:
1. Telling me that an application attempted to access system on your device without authorization and that the attempt has been blocked.
2. Telling me that the Wifi Connection is unstable and that I should enable Wifi Switch (Automacting switching between cellular and wifi).
But now I have to connect even more than two times to get a working connection.
So I restored my phone already, put it to factory settings, same thing. When I called the customer hotline, they did not even get the problem (Maybe because English was not their strongest suit) and when I went to the shop, they told me that that is normal (No, that is not normal).
Maybe one of you can help me or maybe has similar experinces with the phone?