Unable to set SmarterMail as default mail server due to an error:
Error: Unable to set SmarterMail Server XX.XX as the default Mail Server: defpackagemng failed: Unable to assign port to IP address. Reason: Unknown IP Address: (Error code 1)
MailEnable was not properly stopped.
Stop all services of MailEnable and try switching to SmarterMail again.
If the step above did not help, do the following:
Local_Machine > Software > Wow6432Node > Plesk > PSA Config > Configset
MAIL_PROVIDERW_DLLparameter with path to Plesk
smartermailprovider.dlllibrary, e.g. "C:\Program Files (x86)\Parallels\Plesk\admin\bin\smartermailprovider.dll"
2.2. In Local_Machine > Software > Wow6432Node > Plesk > PSA Config > Config > Packages > Mailserver set Default to
2.3. In Plesk Home > Tools & Settings > Server Components click Refresh button