Did you find a solution for this problem? A friend's situation is similar.
With an iMac, iPhone and two iPads connected to the home WiFi, the iPad Air 2 isn't able to connect to the internet. The iPad Air 2 is on the latest iOS 11. Sometimes it can connect, but most of the times it can not, especially if connected to other WiFi networks before. Then it has happened that it forgets the password for the local WiFi or is just unable to connect. All other devices are working fine.
If I configure the iPad Air 2 manually (IP, mask, router), a green checkmark shows up in the settings at the selected network and the WiFi symbol shows quite a good signal strength, but there's still no internet connection possible with Safari.
If I set automatic configuration on the iPad Air 2 for the home network, the network setting gets a wrong mask (255.255.0.0) and the IP is not corresponding to the network. Then no green checkmark is shown and no internet connection possible. In that case it doesn't ask for a password, what makes me think that there should be no other network with the same name and strange mask around.
Making a WiFi analysis from the iMac gets:
- There are many devices around. But, if I disabled the iMac WiFi, there should be at least one additional channel of the 2,4 GHz band available for usage again.
- There are some WiFi networks not having consistent local settings. The strange thing is, that in the analysis the own network doesn't show the correct country code. I might set this up somewhere in the router, but it shouldn't matter so much, should it?
- The general signal strength isn't good, set up a repeater, etc. The iMac I used for analysis is placed in another room that doesn't have a good signal strength and therefore is usually wired, but even if the iPad Air 2 is taken directly nearby the router, where the signal should be good, there is no internet connection with Safari.
I don't own iOS devices personally, so please don't mind some dumb questions:
- How can I soft reset the iPad or the iPad's WiFi module?
- Is it just pressing system recovery in iTunes to full erase the iPad Air and install the last backup?
- Other things I could try?