I've been seeing this a lot recently as I'm trying to do some research into some Minecraft 'golden age' history.
I find a result in Google or on another website to Minecraft Forums, but I get a Forbidden error page like the following:
HTTP Code: 404
Status Text: error
Date: Mon Jan 14 2019 19:02:35 GMT+1030 (Australian Central Daylight Time)
Request: GET /servers/ad
Is this because these threads have been deleted? If so that's a shame for historical reasons. I notice with this one example the user who created the thread's account is also deleted.
(In this case I could get the Google's cached version so i found what I needed. According to that the thread was intact on 25 Nov 2018.)
Unfortunately a large amount of content was removed from the forum over the weekend, including the thread you've provided a link to. You can read more about why in this thread: https://www.minecraftforum.net/forums/forums/forum-discussion-info/2943486-what-is-up-with-all-the-user1234567-name
Monotonehell, you may be able to find archived copies on the Internet Archive: archive.org.
For example, I found that page here: https://web.archive.org/web/20171128204718/https://www.minecraftforum.net/forums/mapping-and-modding-java-edition/minecraft-mods/mods-discussion/1342945-hmod-server-port-v169-teleport-server-to-server