Since about Tuesday last week something has been going on with Discord, and all HH Channels have been marked private except #Help. Sorting that out probably takes all time developer and admins have available.
More info on Discord Help channel pinned posts and the #posts -channel.
All Discord invite links are canceled, that is why the link at top of this page stopped working. I use Discord app on my Ubuntu Linux, and have been able to log in just fine.