after restoring my IOS 11 to IOS 10.3 i cannot ...

Dear sir,

After updating my iphone5s IOS 10.3 to IOS 11 camera not functioning properly.so i planned to degrade my IOS 11 to IOS 10.3 after Degrading i cannot able to activate my iphone "it show Colud not Activate iphone".kindly provide me solution to slove the issue.

Thanks & Regards