Originally Posted by juzek666
Thank you for your answer Marcel. But unfortunately i already have disabled vibration on channel Notifications (and on 2 others - Warnings, Errors).
On Android versions with notifications channels (Android 8 Oreo and later) apps have no control over how notifications are displayed/behave after the initial creation of the notification channel. The whole intention of the notification channels is to put the user, you, in control of notifications, not apps. So, you'll have to dig deeper into the Android notification settings to get this resolved.
You could try to uninstall and install FairEmail again as this will delete all notification channels and recreate them with the default attributes. FairEmail doesn't touch the vibration attribute, as you can see here
, so the default will be the system default.