This error message appears on the client in the log "C:\Windows\CCM\Logs\WUAHandler.log"
Failed to download updates to the WUAgent datastore. Error = 0x800b0109
The reason for this is a self-signed certificate which was stored in the configuration of the patch catalog for SCCM. The following steps must be completed on the target machine for an installation of a 3rd party patch to succeed:
1. The self-signed certificate must be installed on the local machine under "Trusted Root Certification Authories" and "Trusted Publishers"
2. In addition, a group policy must be activated on the local machine. Under Computer Configuration> Administrative Templates> Windows Components> Windows Update
3. In addition, the registry can be checked on the local machine to see if the group policy works