How do I fix the 'Passcode Expired' notification that keeps appearing on my iPhone?

LRB1961 wrote:

When I opened my iPhone screen, I keep receiving a notification that my passcode has expired. It won't let me go past and it wants me to type in my current password, then it doesn't accept it. I went online to change my password and it took the new password; however, this notification continues to come up and lock my screen. How can I correct this? I'm sure I've been hacked but don't know what to do...

[Re-Titled by Moderator]

It's not possible to change the passcode online.

You have not been "hacked".

Do you have a corporate email account configured on your phone? They can set and enforce policies for passcodes, lock timeouts, etc.

Contact your IT department.