iMessage not working :(

if you have enough knowledge please let me know how to solve this problem

originally I created a new Apple ID(********@iCloud.com) on iphone5s

I enjoyed iMessage with friends pretty much there

then I shifted usim chip to iphone7

and I logged in this Apple ID(********@iCloud.com) here

once again I enjoyed iMessage on iphone7

however when I tried to use iMessage on iphone5s

it doesn't activate and I can't use

some sort of identification like inserting numbers of the text message from apple server

does not work and just it shut down

same phenomenon occurs on Mac computer

it doesn't activate

so I can use iMessage only on iphone7

apple said that users can use iMessage regardless of the platforms

iPod iPhone Mac iPad