A web cache is an external server.
I can’t speak for everyone else, but I think my issue was caused by a transient issue with JetPack servers. It went away when I deactivated JetPack, and I’ve had JetPack back on for a while now with no issues.
Never mind. I found that turning off jetpack solved the problem. And it still worked after turning jetpack back on, so I guess it was some weird transient caching problem.
I’m seeing this same (or similar?) error:
This site can’t be reached
The webpage at https:/<mysite>/s/wp-admin/post.php?post=7024&action=edit might be temporarily down or it may have moved permanently to a new web address.
ERR_HTTP2_PROTOCOL_ERROR
I’ve been gradually adding to this page, and now I get this error whenever I try to edit this page. It renders fine when not in edit mode, and I can edit other pages on my just fine. Perhaps it may have gotten too big? If so, any suggestions on how to trim it down so I can edit it again would be greatly appreciated.