After I updated my iPhone 4 to iOS 4.1, I get a PDP Authentication error while trying to browse the internet over 3G. Everything works fine over wifi, the problem only occurs when I use 3G or GPRS. How can I solve this? A: I have figured out why. After the upgrade, my APN settings were wiped. It happened to me before in OS 3.0 with my iPhone 3G. Q: How to reconfigure my APN settings? A: Set your APN information again via Settings =>; General => Networks =>; Cellular Data Network . Then I entered for my provider, vodafone, the following APN Settings:APN: live .vodafone.com
TIP: Forgot your APN Settings please find them in THIS post. After that, it was solved immediately. I had internet and no PDP popups anymore!