Cannot add categories to taxonomy

That looks like the edit screen for a specific term, not the add screen. I imagine there’s an “Update” button at the bottom of it, your screenshot is showing some extra fields and whatnot available.

The add screen would be similar to https://www.yourdomain.com/wp-admin/edit-tags.php?taxonomy=category

We don’t do anything specific that should be affecting those screens, for what it’s worth.

Hi Michael,
Thanks for your quick reply!
I re-read my initial message and it’s confusing…
I’m actually trying to add tags to the custom taxonomy I created on posts such as https://[domain]/wp-admin/term.php?taxonomy=technique&tag_ID=510&post_type=post&wp_http_referer=%2Fwp-admin%2Fedit-tags.php%3Ftaxonomy%3Dtechnique
Is that possible?
Thanks for all of your help!
I truly appreciate how responsive you are on support forums.
-Josh

Still should be, as long as the taxonomy/post types are associated properly. Like I said originally, we don’t do anything specific that intently touches those screens.

Everything else should be getting handled by WP Core itself.

the term.php part of your example url has me wondering if you’re on an older version of WordPress too. I recall something about a recent major release moved urls to edit-tags.php or something. Shouldn’t be causing a problem as a whole, just something observed.

Interesting. It’s running WordPress 4.5.3. You have a login for the site if you want to take a look.
Thanks again for your help!

Can you email me the domain/user? I don’t recall having one. michael @ webdevstudios.com will reach me

Able to log in and find where you’re pointing me to, but I’m not having any trouble adding or editing or associating terms with the ‘post’ post type. The “testing” term is from me.

Any changes, Josh?