Borg Backup - no emails despite Email working

Hey there,
I have a problem with my aio installation and hope someone can help me.
Installation wrnt flawlessly. Borg Backups work most of the time (just one time i saw an error) but i geht no messages about the Backups. I checked the Box to get Info about succeeding Backups. I sent a testmail from nextcloud itself. Nothing
What i did shortly after install. I deleted the admin and promoted a user to ne admin. Any ideas?
Thank you in advance.