Email sender not working

[OH2TH]

Did you check the existing thread about this?

Email sender app not sending mail?

I have installed and configured the Email Sender app. When testing the configuration (on the apps configuration screen), it gives a succes message and I can see the message coming in at my synology mail. When setting up a flow, even a simple one, it does nothing. The action seems to keep running (rotating disc), nor do I see a message in the SMTP logs of the Synology. Is there a way to troubleshoot further?

It suggests that you should restart the app after configuring settings.