Going back to the classic editor on WordPress

Maybe the new Gutenberg editing experience is the present and future of editing in WordPress -- but it's been giving me a lot of headaches so far. I've been getting "Updating failed" and "Publishing failed" messages. Also the Preview doesn't work. I looked at posts like the following for help -- but to no avail:

I'm just punting and going back to the Classic Editor using Classic Editor | WordPress.org.