My copy-paste menu app doesn't paste in Mojave

I've been using a little app called ClipMenu for years. Lets you keep a record of all you put on the clipboard (you might only keep 5 items, you might keep 100).

Great for when you play around in a text, or when you're the type to forget you just copied something and haven't pasted it yet... and you go on and copy something over it. "Don't worry, you didn't lose it!"

So, for the past few days (weeks? I'm bad with time) I noticed it didn't work anymore. I still can copy and past using the keyboard shortcuts, but not the little menu app. The items appear in it when I copy, but if I hit the paste button, nothing shows up.

I tried pasting in different apps, in case ONE app prevented such pasting... but it's just the OS not working with the app.

I figured maybe the app was too outdated, so I went on the app store and got a recent app which does the same thing "CopyClip". I had the exact same problem! So, clearly the problem is with Mojave...

Anyone has an idea on how to make this work again?