Within the configuration file /home/admispconfig/ispconfig/web/roundcubemail/config/main.inc.php there is a line which shows: $rcmail_config['default_host'] = ''; The result of that default line is that the server field is displayed at the RoundCube login screen. If you change that line within: $rcmail_config['default_host'] = 'localhost'; you can remove the server field, so it's not displayed anymore. If you like a pulldown menu with all your hostnames in it, you can replace that default line $rcmail_config['default_host'] = ''; with: $rcmail_config['default_host'][] = "server1.domain.tld"; $rcmail_config['default_host'][] = "server2.domain.tld"; $rcmail_config['default_host'][] = "server3.domain.tld"; $rcmail_config['default_host'][] = "server4.domain.tld"; (The hostnames "serverX.domain.tld" are just mentioned as an example, use your own hostnames instead).