unable to activate iphone 6+

iPhone 6+

***

SERIAL NUMBER : FK***5QH

Hi dear Apple support, i have an iphone 6+ and i just restored it, and now for 3 days it keeps saying "Could not activate iPhone"

"your iphone could not be activated because the activation server cannot be reached, try connecting your iphone to itunes to activate it, or try again in a couple of minutes."

i have also tried with activating it to itunes and it says a message in this screenshot below

the sim card is inserted correctly

please help me asap if possible