A license was installed for the paid Plesk Premium Email version, however, the following warning is shown in Plesk Premium Email:
This domain is configured for Plesk Premium Email - Free, but should not
Plesk Premium Email - Free permission is enabled at Subscriptions > example.com > Customize > Permissions
- Log into Plesk
- Go to Subscriptions > example.com > Customize > Permissions.
- Disable Plesk Premium Email - Free.
- Click OK
Note: If the option is not enabled try to enable/disable it to re-apply the settings.