'''iPhone 6s won’t connect to wifi, always wrong password'''.
So this annoying problem came to me too. I did a lot of tests The situation was
(1) My iPhone 6s could not connect to any 2.4GHz wifi. It complained always about wrong password. By any I mean all my 4 working wifi routers and all the wifi at my friends places, public libraries, train stations, airports etc.
(2) Removing password on the router just made the iPhone change the error message to “unable to connect”.
(3) When I place the iPhone just beside the antenna of the router, within 10 cm, it can connect without problem, with or without password. Tested on several different routers, also on wireless personal hotspots (tethering) from other iPhones and Androids.
This (3) was the most strange and unexplainable thing, refer to (6) and (7) below.
(4) It has no problem with 5 GHz wifi, no problem at all. Also with the same SSID and the same encryption protocol and password.
By now, it is already clear that this is not a software problem. So the next one was not necessary.
(5) Reset the phone to factory settings (or any other resets) and upgrade to newest version IOS did not change anything. Please don’t suggest resetting the router, I can’t do that for all routers in the world.
You might think that the phone must have a defect 2.4 GHz antenna. But then
(6) It could see all 2.4 GHz wifi as good as another “good” iPhone 6s could.
So receiving ability was good enough.
(7) When I set both this iPhone 6s and another good iPhone 6s as personal hotspots (tethering), both turned out to be on 2.4 GHz (You can’t on an iPhone really specify which one you want, can you? I can choose wifi band for Personal Hotspot on my Android phone), and measured the sending strength, they were exactly the same.
So sending power had no problem either.
(8) Wifi client could only connect to the personal hotspot on the good iPhone, not the defect one.
(9) Apple shop / Service Center tested the iPhone with all possible devices but could not find any problem. Well, not surprising. Although I did not have any of the equipments they had, I still think that my troubleshooting was as good as theirs.
After almost one month long struggle, Apple finally decided to replace my iPhone with a brand new one.
So conclusion: iPhone’s 2.4 wireless network can easily break down, reason unknown.
If you guys experience similar issue, and when you go to Apple shops, the phone then can connect to wifi there without problem, it’s because in Apple shops they have 5 GHz. Make them try it on 2.4 GHz wifi, and if they can’t make the phone connected, insist on having a replacement.