sim card has been changed

[marlboro]

i have a sony ericsson xperia play (r800at).  a few weeks ago i received a message saying my sim card had been changed.  what does that mean?  how do i fix?

[Dr_Chris]

Are you still getting a network signal and able to make/receive calls? Was this message from your mobile network?

[marlboro]

i am still able to make/receive calls.  the message ran across the top of my phone stating - warning your sim card has been changed.

[marlboro]

one other thing that may help.  i had perviously set up a patter screen lock on my phone.  i was unable to remember the pattern and after a few attempts the phone was locked.  i called at&t and they re-set the phone to the factory settings.  i had to turn the phone off and when i turned back on that is when the message appeared.

[Dr_Chris]

I don't think it's anything to worry about, but you can contact at&t to make sure.