Apple users are at risk from an iPhone scam in which an error message asks for US $80 to help "fix your phone." This is indeed a scam, and you should not select “ok.” The scam is a virus and will freeze your iPhone.
Thankfully, there is a very simple way to get rid of the message and to remove the virus, and Guides has the answer:
If your Apple device is frozen by this warning message, take these steps:
1. Press the Home button to exit Safari.
2. In Settings, enter Airplane Mode.
3. In Settings, look for Safari settings, and clear your Internet browsing history and cookies.
4. Reopen Safari and the pop-up warning should have gone.
5. If the scam message has gone, take your device out of Airplane Mode.
By Martin Fullard