I can't post a reply to a thread I started.

I was getting that "something went wrong" error for a while, but I think it was fixed.
I always had to refresh the page, and then repost my answer/reply. Give that a try.

Now I get 404 error when I go to reply from email on two computers. I can't even locate my title "import screwmodel to cad" (yes I ran two words together)

I don't think there was anything offensive or controversial in the post, so it seems unlikely that it was deleted.
It is odd that it just disappeared though.