There was no attached screen.
However, I assume mine will suffice:
Hover over the X to find out why the gateway does not have a green checkmark.
In my case, it is because there is no SIC connection with this gateway (it's actually a non-existent gateway).
Likewise, when you hover over the N/A status under Recommended Updates, you will see the reason.
Specifically, this feature is only for R80+ systems.
For troubleshooting SIC, start with the product documentation: SmartConsole R80.10 Help: Gateways
For more detailed troubleshooting, refer to the following SK: How to troubleshoot SIC