SymptomshMail-3.x was installed and configured to work with a remote MSSQL server. hMail service has been configured to run on behalf of a user having access to the remote MSSQL server and not the SYSTEM built-in user. Plesk indicates that the component is present but is not configured.
CauseThis problem can't be resolved on hMail-3.x.
All Plesk utilities work on behalf of SYSTEM user and are not able to connect to remote MSSQL servers using SYSTEM user.
ResolutionThis problem can be resolved only using hMail-4. It can be properly configured to use remote MSSQL servers by editing the hMailServer.ini file.
It's necessary to point username and password for access to a remote MSSQL server, otherwise hMail uses Windows authentication.