You are customising (Untitled)

I added a few plugins to improve the speed of my site, and also installed yoast to change the title tag, and for some reason now i can’t update the content of the site in the live preview mode.

I’ve disabled all the plugins i installed and still have the same problem.

In the customise menu, at the top of the page, it says “You are customising (Untitled)”

When i try and press the Open Reiki Front Page button nothing happens.

Thanks