If you use nginx see this doc
Check whether this is enabled (no # at start of line) in the config
# optionally, additional sub-urls can be proxied to the application, like
# /link/ when using the deeplink widget, which registers a request handler
# on /link/
# note this one does not have the equals sign after location, because the
# link widget uses urls like /link/blahblah, and not only /link/
location /link/ {
proxy_pass http://127.0.0.1:8000;
}
and check your runtime definition of the deeplink