A user of my app did not get a notification email some time ago where he should have got one. The problem has occurred about four weeks ago, in the second week of Nov. But I became aware of it just yesterday when the user contacted me.
For clarification, the app is a turn-by-turn gaming app, users are notified by email when it is their turn. The user of concern usually gets his emails, but this time no email was sent to him at all, as I could check by just inspecting my Sent folder. I am using flask_mail.Mail in my app.
I would like to investigate what went wrong, but I do not know where to look. The error and server log files (on /var/log) only go back to early December. Would problems with mail show up in these log files at all? Or where would mail problems be visible?