What does this mean?

API Request Failed: GET /api/v4/accounts/21284fbd9222764de164feb59de30be7/registrar/domains/teachmewine.com (503) :roll_eyes:
on dns page.

This is most probably just an internal thing on CloudFlare side.
I also encountered some of these error.

503 stands for “Service unavailable”.
I think these errors will go away over time. May they are currently working on APIv4. But anyway I did not encounter any misbehaviours or functional limitations due to this errors.