I had this issue during the beta, but was never able reproduce it, after i rebuilt my page from scratch. Now it happened again.
After adding a set of buttons and styling them, the “Uh oh!” error message came up.
Safari console gave me this error:
Failed to load resource: the server responded with a status of 500 ()
MY-URL/wp-json/themeco/data/save?_locale=user
Added login credentials and another error in the secure note.
Weird thing is, i cant add new wordpress users to my site. Don’t know if this is related to the issue mentioned above tho.