403 userRateLimitExceeded Indicates that the user rate limit has been exceeded. The default value set in the Google Cloud console is 2,400 queries per minute per user per Google Cloud project. Increase the per user limits from the Admin SDK API Quotas page of your Google Cloud project, or slow down the rate at which you are sending the requests using exponential backoff.
403 quotaExceeded Indicates that the limit of concurrent requests for a certain operation has been reached. Retry using exponential back-off. You need to slow down the rate at which you are sending the requests.
429 rateLimitExceeded Indicates that the limit of concurrent requests for a certain operation has been reached. Retry using exponential back-off. You must slow down the rate at which you are sending the requests. This limit is per Google Workspace account, not per API client or per user. This limit can't be increased.