Many iPhone 6s and 7 plus, even iPhone 8 users are facing issue to join WIFI network after upgrading to iOS 11. User is not able to join wireless network as able to do with iOS 10 on same network. While trying to connect to network iPhone user receives a pop up “Unable to join network”. The issue is also reported on iPad devices. iPhone “Unable to join network” error is mainly reported for wireless network over Routers only.
Most of the apps work with Wi-Fi and it will make them useless if iPhone is not joining to WIFI networks.
How to fix iPhone “Unable to join network” issue.
Fix 1: Change Router settings
The error message “unable to join network” seems to occur with specific Wireless Network routers, So if your router support dual band routing try to test connection with other network.
Change the router settings eg to choose channel “6” instead of “Auto” or e B+G instead of B+G+N. (depending upon router model) Also change the security to WPA2 from WPA. This should fix iPhone not able to join the wireless network issue.
Fix 2: Restart Router and Restart iPhone or iPad
Restart Router: just power off your router and power on it again. And once done Restart iPhone, now try again to connect to WiFi.
Fix 3: Reset Network Settings.
Reset Network Settings: Settings > General > Reset > Reset Network Settings. It’ll require you to put your password. And this operation will disconnect all Wi-Fi networks and erase passwords you’ve entered. Now set up again to connect to Wireless network.
Fix 4: Upgrade to latest iOSWIFI issues and similar network issues can be fixed by Apple in upcoming fix. Latest iOS 11.2 seems to fix many iOS network issue but also reported with WIFI dropping issue. Hopefully Apple will come up with permanent fix for these issues