Maybe nothing!
First, you cannot accurately compare "checking online" with using a WSUS server, so don't try. Elsewhere in this forum I wrote a 300 word explanation why this is an exercise in futility.
So, plain and simple, you need to identify which updates are NotInstalled on that server, and then take the appropriate actions based on why they're not installed.
Find the server in All Computers, right click, run a Status Report. Filter the report on updates with a status of "Needed", "Failed", or "No Status". Now you have a list of updates. Are the updates approved? Are the files downloaded for these updates? Are
the updates superseded?
Lawrence Garvin, M.S., MCSA, MCITP:EA, MCDBA
SolarWinds Head Geek
Microsoft MVP - Software Packaging, Deployment & Servicing (2005-2014)
My MVP Profile: http://mvp.microsoft.com/en-us/mvp/Lawrence%20R%20Garvin-32101
http://www.solarwinds.com/gotmicrosoft
The views expressed on this post are mine and do not necessarily reflect the views of SolarWinds.