Failed to install update for Virus and Spyware Definitions SDS Win64 (Reduced)

I have a SEPM and SEP client  (v14) installed in the same server with 30+ clients replying on the same server. All client can update virus definition successfully except the Server client itself.  I think this is not the problem of luall.exe cause other clients can successfully update except the server itselt.  But when i run it, I got LU1806 & LU1825 error.  Did anyone have the same problem? Or at least can anyone give me a clue of where the problem might be. Thanks a lot! This drives me crazy.