There is nothing "Premium" about the install process for Plesk Premium Email
The install fails because dependancy guam isn't installed.
Manually install guam.
Re-run installer and error :
filemng failed: cp: cannot create regular file '/etc/roundcubemail/php.ini': No such file or directory...
This is working for me on S3, but one subscriber uses OneDrive and that appears to still be failing.
Warning:
Unable to create the remote backup: Transport error: Extension transport: ext://one-drive-backup/subscription/3/: Microsoft OneDrive returns the error: The object specified does not...