How to refer to a message in different server?

I saw that messages have different identifiers on different servers. What should I write in my text to make the hyperlink to work on all servers?

https://xn--e1aghfa.xn--e1aqbccjfc.xn--p1acf/post/15
https://lemmy.ml/post/49064481

15 ≠ 49064481

The site https://lemmy.ml/ is unreachable from my computer because of government politics. I want to refer to the copy of message, which is downloaded into my instance. But it have a new ID in my DB.