When I struck this problem myself I had the seat-of-the-pants feeling that this is a big high level problem. Now after reading quite a few comments, troubleshooting guides etc. I'm still thinking this view may be true.
My original experiences are two. One is that my own Samsung "Galaxy 5" model or I5503T will successfully connect to an Asus router model RT-N11; but two, it will not connect under any amount of fiddling with a TP-Link TL-WR941ND router. In the 2nd case I was attempting to connect a customer's Sony Android which also refused and I used my own Samsung to try to ascertain whether the problem was the router or the phone. I have not been able to test my client's phone on my Asus router - too inconvenient!
Further, the Samsung connection to the Asus often has to be forced by the power off the phone power it back on method. This is irritating and inconvenient! When it's connected, where obviously one has to be in range, if one walks out-of-range and walks back in again it won't automatically reconnect. One may, or may not, have to do the power off power on trick again!
Also the problem has another form. That is with the TP-Link router the phone sees the SSID and upon connecting to it, with or without security and password, it will then fail saying the router is "out-of-range" when one is sitting about a metre away doing this attempt.
(This posting was held up for a couple of days due to an authentication issue. Since then I was able to check out my Samsung with another TP Link and a Netlink routers and it connects to both but there may have been a relevant update or upgrade that went onto it when something else was updated from Google Play).
I have been in touch with TP-Link tech support and they were stumped. Together with my hardware supplier we are trying to identify a brand of router that does not have this or such problems. My dealer confirmed the problem with his phone and said he was going to check his phone out at a free Wi-fi spot but I haven't heard back from him yet. Is there something wrong with that particular model of TP-Link?
Conclusion: I think there may be problems with the specification for implementation of the Wi-Fi protocol.
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