No longer able to add shortcodes

For the path, /wp-admin/edit.php?post_type=shortcoder, it says…

You need a higher level of permission.
Sorry, you are not allowed to edit posts in this post type.

I am the only administrator. What can I try next to help resolve this issue?

The issue is the same as was asked 10 months ago; https://www.ads-software.com/support/topic/administrators-on-a-multisite-can-no-longer-add-shortcodes/

But, in my case, it is not a multisite.

It is missing “All Shortcodes” and “Create Shortcode”. So, not possible to add or change any of the shortcoders.

The page I need help with: [log in to see the link]