urkrob wrote:
Same problem on Australian iPad 16gb wifi - surfing Internet, suddenly get the modal box telling me password incorrect.
Try a few times, give up, disable wifi for a few minutes. Enable again and without re-entering password, suddenly works again. How is that an incorrect password???
More like a driver or hardware issue in the iPad.
This is not a necessarily a solution but, perhaps, will clarify what probably is happening when the iPad presents a box indicating that your password is incorrect.
Your password is used to encrypt traffic between your iPad and your router when a connection is first made. When you are connected the situation is more complex since the actual text encryption key is being periodically changed. As you have discovered, the iPad has not forgotten the key but, for some reason, it is having problems reestablishing a connection with the router. After some number of tries it gives up and assumes that the key it has is no longer valid and asks you for a new one. If you re-enter the password it will try again. This time the connection may be established or it may not.
The underlying cause could be a a problem in your iPad, a problem in your router, a problem in both the iPad and router (spread the blame 😉 ), or there could be some interference on the communication channel frequency that is being used. Try your iPad on a public network, e.g., Borders, Apple store, etc. If you don't have problems there then look at your router. Does it have the latest manufacturer firmware? (visit the manufacturer's web site support page). You could also try resetting the router. In addition to checking your router check to see if there are other WiFis in your immediate area and switch to a different channel to avoid interference.
By the way, this sort of problem seems to be more common if WEP security is being used. If you are using WEP you could try moving to WPA security. WEP is not really secure (a hacker can crack it in seconds).