Error: "Name of database connection must be specified. Default database must be specified if an application server exists." when launching ITSM 3 tier connection.
This error happens when the 2 tier connection gets changed and is not synced with the settings in the web.config file (C:\Program Files (x86)\FrontRange Solutions\Service Management\ServiceManagement) - see below screenshot for path and setting.
Verify the correct connection name is listed and correct if needed and reboot the server after the change.