Verify the DNS configuration of your system and then restart the entire system. If the above actions do not work, then you will need to contact the system administrator or the help desk. As the problem with connecting to the WebMail server is caused by configuration or availability problems, make sure that users who report this problem have HTTP network connectivity to the hostname. Users are being blocked by firewalls. Users are connecting from the wrong network.
Users specify the incorrect DNS servers.
In addition, users may also report that the server is down. As the login page for WebMail does not contain URL links that are FQDNs or absolute path names, it is possible that users may still be able to see the login window if it was cached or loaded before the server stopped working. In some cases, it may be necessary to access the hostname that is used in the WebMail links. This hostname setting is stored in the configdb parameter service.smtp.messagehostname . This configuration setting is not mentioned in the Messaging Server documentation.