iMessage not working after changing MAC address

My iMessage is not working after I have changed my MAC address. I have restored my original MAC address, but it is still not working. My phone is an iPhone 4s, 6.1.3 jailbroken.

I changed my DNS, restored with iLex RAT (because I don't want to upgrade to iOS 8), then reset network settings, but it is still not working. How can I resolve this?