LiveUpdate Administrator (LUA) 2.3.8 cannot send test mail when [Notify when tasks complete successfully] is not checked in [Preferences] page.
Following error appears in top section of console.
Please enter valid mail ids @,. and _ special characters are allowed.
Some parameters contain invalid values. Please re-enter.
LiveUpdate Administrator 2.3.8
This is by design. You need to enable [Notify when tasks complete successfully] when sending test mail in LUA 2.3.8.
If you do not want to enable this option, enable it once and send test mail, then disable it again when you receive test mail successfully.