I know this is an older post, but have you been able to figure out the job ID once its been run in sandbox. Sometimes I don't get a check status link with the job ID and if I run it again as a new query it says the job already exists. This is to prevent multiple API calls for the same group. I was testing my python code and was trying to make a call to the API to see if a job exists, what was it but was unsuccessful. Once the job ID is found, you can make a get request to the url with the job ID at the end with your access token to get the NDJSON files but its hard to find the job ID once it starts on sandbox. I hope this is easier in production if the job ID exists on the clinics front for their group query results when they make their access groups. Any help would be appreciated to find sandbox job ids if it returns with this message.