if you want to track someone from the internet use Grabify.link.. you can easily get their IP address just by sharing that person any random pic and once they click to it that should give enough information to track the person (just read the instruction on how to use it). it's applicable in messenger as well.
Tried to login to the site you mentioned but it says invalid hostname.Can you give me the exact link to do that.
https://grabify.link/ Try this one mate.
okay instruction is,
for you to be able to locate the person u need to send him/her a message.. to do that u needa grab a random picture from google or any random link u want (it could be a website link or a cat photo as long as its a short link) and then u enter "create link" then it should show you "new link" and u copy paste that to the person u want to send it to (do not exit the link because once the person clicks the link it will show there where that person is.