Recently worked on a 2008 SP2 server that was receiving error 800F0902 when trying to check for updates. I confirmed access to the WSUS server manually via Internet Explorer and also confirmed no proxy settings were coming into play. I tried the age old trick of stopping the Windows Update service and renaming the C:\Windows\SoftwareDistribution folder to SoftwareDistribution.old and restarting the service. This regenerates the Windows Update configuration for you. This stubborn error survived that reset, so I finally came across a Microsoft FixIT KB article to fix Windows Update problems. I’m quite skeptical of using these, and I prefer to know exactly what’s being fixed, but without any other options, I decided to give it a try. No surprise, it said it found a configuration problem and fixed it, but the error persisted. A few other posts suggested an issue with trustedinstaller.exe (aka Windows Module Installer Service) so I gave that a restart and started receiving 80080005 errors. Another post suggested that after a reboot, this error cleared for that user. Sure enough, a reboot solved the problem for me as well.