Application domain not authorised, crashes page

My site is a subdomain and something seems to be setting off the ‘application domain not authorised’ error. Weirdly it’ll only pop up after about 20 minutes of me working on the site, randomly start working again after a few minutes, hours or even days pass, and repeat.

I’ve made my API key with adobe (I’ve actually tried different times, trying both subdomain.domain.com, and just domain.com).

When the error occurs on the post editor, I’ve tried re-entering the key in the side bar, but it seldom helps, and often crashes the entire post page – nothing can be clicked on.