No Option to Allow Comments

Have you tried:
– Flushing any caching plugins you might be running, as well as server and/or browser caches. Also, any op cache or content network cache, as well as Cloudflare, clear those caches.
– deactivating ALL (yes all) plugins temporarily to see if this resolves the problem (plugin functions can interfere). If this works, re-activate them individually (one-by-one) to find the problematic plugin(s).
– switching to the unedited default Twenty Fifteen theme for a moment using the WP dashboard to rule out any theme-specific issue (theme functions can interfere like plugins).

This might be a bug in your theme. The template responsible for showing comments might be ignoring the comments and displaying the message instead.

However that doesn’t explain why you don’t have a discussion checkbox in screen options. It should be there, unless you are editing the posts of a post type that doesn’t support comments.

I’ll try the above and report back.

Looks like Advanced Custom Fields caused it.

glad you got it sorted ??

Haha. Just wish I could go without it! My theme requires ACF.