If you are seeing a "Too Many Requests" error message upon a job failure, it means that the third party app (example: CRM app) you are using in conjunction with Flatly imposes an API call limit on your account and Flatly is hitting that limit.
The two best solutions are:
(1) Stop all running jobs and run the problematic job an hour later, by itself.
(2) Contact your app provider and ask them to raise your API limit.
Some APIs are more robust than others.