Happens most times because the servers are created from an AMI (never syspreped)
Note: All other servers are reporting to WSUS such as Windows server 2008R2 and Server 2012 R2 but Windows Server 2016 does not.
Note: All registry keys are created on Server 2016 and there is connectivity between the wsus server and the windows server.
Solution: Delete the SusClientID and SusClientIDvalidation keys from the registry. This is because the sever was created from a clown (AMI) and new ones will be generated automatically.
- Stop windows update service
- Delete SoftwareDistribution folder
Run the commands below from the commandLine
wuauclt /resetauthorization /detectnow
And this as well
wuauclt /detectnow /reportnow