go. Why is the handler not working?

Question

go

If you work with some handler for a while, then for some unknown reason it stops processing a request for a certain cookie.
If you change or delete the cookie, then everything is fine for a while. Or change the host from: 8080 to any other. With the domain is the same shnyaga.
It's not even about the cookie, but in the browser, if you open it in incognito and put this cookie, then everything is fine.
The problem has been around for about two weeks now.
Example:
There is a link "/link", get requests come to it, everything is fine.
It stops working, gives 404 page not found.
It doesn't matter if you use any framework or native libraries, the problem remains.

Answer 1

gin?