Problem WSUS Server and SCCM Server

Hi All, 

I have one WSUS server that is in the DMZ zone and SCCM server is in back end. 

Problem is the link between WSUS server and SCCM server.

In WSUS server, all patches has successfully downloaded but not reached to SCCM server. 

Please suggest me on this case.

Thanks,

Mmhein.