Activation Unsuccessful. Turn on Imessage to try again

I can't active imessage and facetime by my phone number (Apple ID still can active)
This error "Activation Unsuccessful. Turn on Imessage to try again"

I have problem about 1 month ago.

I tried everything i can. My simcard is ok. My iphone 6 is ok (I can active imess by other simcard on this iphone)

What can i do?

Please help me! Tks!