I use version 5.6.5 of the ELK stack, running under docker.
I have a watch that is supposed to run once per month on the 1st of the month and send an email with a PDF report attached containing stats for the previous month.
When I simulate the watch via the Kibana UI, it works and I receive an email with an attachment that contains the correct dashboard data.
However, when the watch triggers on the 1st of the month, I receive no email and the only log entry I can find is in my kibana.log, telling me "statusCode": 500".
I've diffed the kibana log entries for the successful manual report generation and the failed automagic watcher generation and apart from the status code and time stamp/duration, they are identical.
Where do I go next to try and find out what is causing this 500 error on the automagic run?
I've added the watch config, 200 reponse and 500 response at https://pastebin.com/EL6qZr7E