Help!! can't send or receive messages.. why?

[bubbles05]

I have tried to google but can't find an answer as to why my text messages won't send and I can't receive any either.
I have had the nokia lumia 800 for a couple of weeks now and I haven't had this problem before.
I can type my message but it won't send, I'm not even getting a message to say it won't send or why it won't.
Can anyone help me? thanks..

[93tid]

Try running the Network Setup app from the Nokia Collection in Marketplace (if available). This app will setup settings for Internet and MMS using many available carrier presets which you can select or you can choose to do so manually.