No automatic synching

I have installed K9 and enabled automatic synching with audio and visual notification, but it is not working. It only syncs when I update the mails manually. Is this a bug in the latest version (5.727)?

Works fine here.

Make sure k9 is excempt from battery optimization in your device settings.

It was already excempted…

Then I have no idea, sorry 🤷🏼