I'm using the Google Calendar API v3 from the Python client. The courtesy limit is 10,000 queries per day. The Google API Console shows that I've used up 471 requests so far today and a total of 1.47k over the last 28 days, which sounds like it is far short of the limit.
I am now seeing HTTP Error 403 Quota Exceeded errors every time I try to use the API. I'm aware there is also a rate limit, but I'm not sending requests particularly fast and I've reset the per-user rate limit to 10,000 requests/second/user using the API Console just to be safe. I'm probably generating less than 5 requests per second, from one instance of a single-threaded application that no one else has access to during development. I've tried sleeping and retrying the query but I get the same error every time I retry.
Is there some other quota (besides the 10,000 requests per day and the per user rate limit) that I am running up against? Is Google's quota system broken?
Thanks for your help.