The 'Error' API endpoint is your endpoint to let the Argus system know the cron job has thrown an error. It can be a simple GET endpoint if you just want to log that an error occurred. You can notify it by simply sending a curl request such as curl https://argus.to/your_unique/endpoint_url/error when you capture the error.
If you are on the Laravel framework, all you need to do is at the `pingOnFailure` directive to your scheduler.
If you wish to pass a JSON message with your error, you can also make a POST request to the same endpoint with your message. An example of that might be something like