In what is surely the oddest fix for what has become the most pervasive set of iPad issues, it appears that adjusting the device’s screen brightness may, in some cases, resolve a problem in which the iPad fails to reconnect to Wi-Fi networks after the unit wakes from sleep.
(Note that this issue is separate from an issue in which users experience weak/fluctuating Wi-Fi signals, inordinately slow transfer speeds, and/or inability to maintain wireless connections [constant drops]. We’ve posted a list of fixes for those problems.)
In this issue, the iPad does not automatically reconnect to a previously connected WiFi network when it wakes from sleep, forcing the user to open Settings a reselect the network. In proper behavior, the iPhone would rejoin the network with no user intervention.
Adjust brightness. Oddly, a number of users have found that they can resolve this issue by simply adjusting the iPad’s brightness level upward and off the lowest setting. To do this, tap Settings, then select “Brightness & Wallpaper” from the left-hand pane. Slide the brightness bar upward, then put your iPad to sleep and check to see if the Wi-Fi reconnection issue is resolved.
Speculation holds that a power delivery issue associated with the screen brightness affects the Wi-Fi reconnection scheme.
Bring up power off screen, but don’t power off. Another odd workaround: when your iPad forgets a network and prompts for the password, instead of entering the key, press sleep/wake/power button until the iPad shows “Slide to power off,” then press cancel. This may cause the iPad to automatically reconnect to the network.