Thank you for looking into it.
It seems that this is a symptom of the other issue i’ve posted, Webinar registration: 404 not found: error code 1001 User does not exist - #11 by Aaron5, where the user registration fails with an inexplicable “404 User does not exist”
Even though the user is not registered, there were 3 failed registration attempts (which happened to yield a 404 response). Those 3 attempts count against the daily quota, and all requests yield the 429 response.
I think this thread can be resolved, and I’ll look forward to a response on Webinar registration: 404 not found: error code 1001 User does not exist - #11 by Aaron5