Follow these instructions to log directly into Hoststar Webmail:
Direct login for Webmail
What login details do I use to access Webmail?
If an email address is linked with multiple email mailboxes, you must log into Webmail with the specific mailbox. The email address required to log into Webmail is the combination of the mailbox name and server name, for example: webXpY@login-Z.hoststar.ch.
The name of each mailbox is listed in the table view of My Panel.