Backups are not physically deleted from Server Backup repository when domains, customers or resellers are removed from Plesk.
This is Plesk internal issue with ID #PPPM-4396, which is planned to be fixed in future Plesk updates.
Delete backups of removed domains, customers or resellers manually from the directories below:
/var/lib/psa/dumps/domains /var/lib/psa/dumps/clients /var/lib/psa/dumps/resellers
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