Since the conversion of the Free Google Analytics connector over to use the newer v4 Reporting API, the project has started hitting it’s API server quotas. This affects all users of the connector and results in a 429 error — Too Many Requests. Further attempts on the same day are fruitless — the quota resets at midnight, Pacific time.
A new release of the Free Google Analytics connector (v5.4.0) will drop back to the old API after the first 429 error. Should you encounter an error, trying again should work.
I have requested an increase in the quota, but that might take some time. Until then, I apologize for the problems.