Meaning of Icons in the Status Column
On MainWP > Sites > Manage tab the Status column shows you the current status of your websites: The dark green icon with a number will show you the number of available updates on your site. The red exclamation mark indicates that the site is down. The green checkmark icon indicates that your site is online. Also, your Status column can show you this icons: The red plugin icons indicates that site is disconnected from dashboard. The yellow radiation icon indicates a plugin or theme conflict.