Configuration Manager did not find a site to manage this client

Using Client Push installation on multiple systems in a ConfigMgr site, gives the following result: "Configuration Manager did not find a site to manage this client". Whatever you are trying, no ConfigMgr site is found. Everything else seems to be in good order, you can ping the ConfigMgr server, the system is within the boundary which is part of a boundary group, and ipconfig /all shows all information with a valid IP-address and DNS server. What's wrong here?

Looking in ClientLocation.log shows the following error: "Attempting to assign client to site *** that does not match assignment requirements". Now let's have a look at that.

Lucky me I found the following post: Microsoft TechNet
It mentions: At some point in the organization someone had implemented a GPO (admin template) to assign the CM site. This GPO was also at some time before me removed; however the registry settings remained tattooed on the client. HKLM\ Software\ Microsoft\ SMS\ Mobile Client\ GPSiteAssignmentCode - Changing this value from the old site to the new fixed the issue.

In my case I deleted all three keys starting with GP and the problem was solved immediately. Just make sure to delete GPRequestedSiteAssignmentCode key at minimum. You will see that AssignedSiteCode key will change automatically after that.

Just great to have it working now!