- Plesk for Windows
- Plesk for Linux
When customer creates a mailbox, Spam filter is turned off. However, it is turned on server-wide at Plesk > Tools & Settings > Spam Filter. In Plesk > Service Plan > Add a Plan > Permissions > Spam filter management it is turned off.
This is Plesk internal issue with ID #PPPM-6031 , which is planned to be fixed in future Plesk updates.
As a workaround, enable Spam protection from the administrative account or enable Spam filtering management permission in the service plan.