Sccm 2016 software inventory not updating
Make sure the permission is flowing to the objects within and the objects below.
If you are not publishing the information in AD then you need to make sure that the SLP is configured and working.
Unable to get the site code If the client is not able to get the site code, you need to check first the boundaries as above, and also verify that the site information is published in the AD.Once this is done you can either make use of the maintenance task or you can create a collection for the NON SMS CLIENTS and then do a delete special to the collection so that the entries will be removed permanently from the SMS\SCCM database.Then a discovery can be run which will bring back only the active systems in the collection.Assuming everything is installed and configured properly, a client installed on a system should automatically report as Yes, but sometimes that does not turn out to be the case.The reason could be that the client has not yet reported to the SCCM\SMS server, or it was reporting previously but has now stopped.
For more information you can check Post-installation phase in the link: The client itself is not installed in the Agent You can take a look at this article which will give you a detailed explanation of how you can make sure that the client is installed and reporting successfully. Make sure that the client is able to communicate to the SMS\SCCM server using the FQDN as well as the Net BIOS name. If you can’t ping the server using the FQDN then you will have problems.