The welcome mat stickies is all that appears.
I would suggest that it would be nice if a person with appropriate skill and power fixed it. 
Same problem for me. Everything else seems to be working OK, but am unable to open this particular thread. Doing so kicks me back to the main forum list.
I couldn’t open it either, so I tried moving it to another category, and now it seems to work ok. Let me know if you still can’t open it.
Weird, never seen that before.
Works for me now, too. Feel free to delete this thread.