Getting the random message "Password Incorrect. Enter voicemail password."
I keep getting the random message "Password Incorrect. Enter voicemail password." Sometimes it pops up when I turn the phone on but other times it pops up several times in the same app, such as sending/reading messages. Other times it does not pop up even though I have used the phone or apps several times without seeing it.
iPhone 4S, iOS 5.1.1