I have a pretty fresh installation of WP running and I keep having the weirdest issue. Whenever I have any contact form plugin active (like Contact Form 7, and Easy Contact Forms), I can't add post categories or any category for some of my other plugins (Woocommerce, Maplist Pro, PrivateContent, etc).
As soon as I disable the contact plugin everything works again. I'm totally stumped as to what can be causing this issue. At first I thought it was a problem in Contact Form 7 only so I tried another plugin and it did the same thing.
I spent hours looking for the culprit and figured it had to be a plugin, but never thought this would be it.
The only other thing that may be relevant is on Friday I was trying a few different caching plugins, but all of them caused other issues so I disabled and removed them. No idea if that's relevant or not.
I have a local copy of the site running with pretty much an exact copy of the DB and files (except I had to do a find/replace on the DB SQL file before importing it so it would have my local domain in it). With the local copy I have no issues whatsoever. Again, I'm pretty stumped as to what can be causing this.
Thanks in advance.