Hi Everyone,
After two weeks of not being able to edit my storefront, I FINALLY found the setting that is triggering this pop-up, so would like to share it with everyone in hopes that it can resolve the issue for you as well.
I am on Safari and the setting that triggered this pop-up for me was the “Prevent cross-site tracking” setting. This box needs to be unchecked.
To access this setting from the current version of Safari:
Safari → Settings→ Privacy Tab → Website tracking → Prevent cross-site tracking
Make sure there is no check adjacent to “Prevent cross-site tracking”
Hope this helps!