For boundary issues you can use this as a reference:
For the case of overlapping boundaries see the client if you check the location (log location: C:\Windows\System32\CCM\Logs), you can get the information of the site assigned to it as well as the MP it is reporting to.
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.
If it is not able to report properly, you need to make sure that the agent can communicate over the network to the site server successfully.
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.
For that you will need to check the mpcontol (Log location: \SMS\logs in SMS and \program files\Microsoft Configuration Manager\logs in SCCM).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.The client is behind a firewall If clients are behind a firewall, it may be restricting it from contacting the SMS site server. You can check to understand the port requirements.If the MP is working fine and the client is unable to contact and download polices, you will have an error on download in the file on the agent (Log location: C:\Windows\System32\CCM\Logs).Before checking this though, check if the has the correct MP information.Managing the client in the collection is a continuous task and for a healthy environment the client should be continuously reporting to the SMS\SCCM server.There are various reasons why a client may not be able to report to even if the SMS\SCCM agent is installed on a machine.var microsoft = microsoft