Windows Update Sync failing. Any suggestions?

WSYNCMGR.log

Sync failed: WSUS server not configured. Please refer to WCM.log for configuration error details.. Source: CWSyncMgr::DoSync SMS_WSUS_SYNC_MANAGER 4/23/2015 2:10:06 PM 8592 (0x2190)
STATMSG: ID=6703 SEV=E LEV=M SOURCE="SMS Server" COMP="SMS_WSUS_SYNC_MANAGER" SYS=GC-VM-SCCM.gcschl.gateschili.org SITE=PRI PID=9148 TID=8592 GMTDATE=Thu Apr 23 18:10:06.853 2015 ISTR0="CWSyncMgr::DoSync" ISTR1="WSUS server not configured. Please refer to WCM.log for configuration error details." ISTR2="" ISTR3="" ISTR4="" ISTR5="" ISTR6="" ISTR7="" ISTR8="" ISTR9="" NUMATTRS=0 SMS_WSUS_SYNC_MANAGER 4/23/2015 2:10:06 PM 8592 (0x2190)
Sync failed. Will retry in 60 minutes SMS_WSUS_SYNC_MANAGER 4/23/2015 2:10:06 PM 8592 (0x2190)
Setting sync alert to active state on site PRI SMS_WSUS_SYNC_MANAGER 4/23/2015 2:10:06 PM 8592 (0x2190)
Sync time: 0d00h05m00s SMS_WSUS_SYNC_MANAGER 4/23/2015 2:10:06 PM 8592 (0x2190)
Wakeup by inbox drop SMS_WSUS_SYNC_MANAGER 4/23/2015 2:58:51 PM 8592 (0x2190)
Found local sync request file SMS_WSUS_SYNC_MANAGER 4/23/2015 2:58:56 PM 8592 (0x2190)
Starting Sync SMS_WSUS_SYNC_MANAGER 4/23/2015 2:58:56 PM 8592 (0x2190)
Performing sync on local request SMS_WSUS_SYNC_MANAGER 4/23/2015 2:58:56 PM 8592 (0x2190)
Read SUPs from SCF for GC-VM-SCCM.gcschl.gateschili.org SMS_WSUS_SYNC_MANAGER 4/23/2015 2:58:56 PM 8592 (0x2190)
Found 1 SUPs SMS_WSUS_SYNC_MANAGER 4/23/2015 2:58:56 PM 8592 (0x2190)
Found active SUP GC-VM-SCCM.gcschl.gateschili.org from SCF File. SMS_WSUS_SYNC_MANAGER 4/23/2015 2:58:56 PM 8592 (0x2190)
STATMSG: ID=6701 SEV=I LEV=M SOURCE="SMS Server" COMP="SMS_WSUS_SYNC_MANAGER" SYS=GC-VM-SCCM.gcschl.gateschili.org SITE=PRI PID=9148 TID=8592 GMTDATE=Thu Apr 23 18:58:56.762 2015 ISTR0="" ISTR1="" ISTR2="" ISTR3="" ISTR4="" ISTR5="" ISTR6="" ISTR7="" ISTR8="" ISTR9="" NUMATTRS=0 SMS_WSUS_SYNC_MANAGER 4/23/2015 2:58:56 PM 8592 (0x2190)
Sync failed: WSUS server not configured. Please refer to WCM.log for configuration error details.. Source: CWSyncMgr::DoSync SMS_WSUS_SYNC_MANAGER 4/23/2015 3:03:56 PM 8592 (0x2190)
STATMSG: ID=6703 SEV=E LEV=M SOURCE="SMS Server" COMP="SMS_WSUS_SYNC_MANAGER" SYS=GC-VM-SCCM.gcschl.gateschili.org SITE=PRI PID=9148 TID=8592 GMTDATE=Thu Apr 23 19:03:56.849 2015 ISTR0="CWSyncMgr::DoSync" ISTR1="WSUS server not configured. Please refer to WCM.log for configuration error details." ISTR2="" ISTR3="" ISTR4="" ISTR5="" ISTR6="" ISTR7="" ISTR8="" ISTR9="" NUMATTRS=0 SMS_WSUS_SYNC_MANAGER 4/23/2015 3:03:56 PM 8592 (0x2190)
Sync failed. Will retry in 60 minutes SMS_WSUS_SYNC_MANAGER 4/23/2015 3:03:56 PM 8592 (0x2190)
Setting sync alert to active state on site PRI SMS_WSUS_SYNC_MANAGER 4/23/2015 3:03:56 PM 8592 (0x2190)
Sync time: 0d00h05m00s SMS_WSUS_SYNC_MANAGER 4/23/2015 3:03:56 PM 8592 (0x2190)

WCM.log

Attempting connection to WSUS server: GC-VM-SCCM.gcschl.gateschili.org, port: 8530, useSSL: False SMS_WSUS_CONFIGURATION_MANAGER 4/23/2015 3:02:37 PM 4756 (0x1294)
System.Net.WebException: The request failed with HTTP status 503: Service Unavailable.~~   at Microsoft.UpdateServices.Administration.AdminProxy.CreateUpdateServer(Object[] args)~~   at Microsoft.SystemsManagementServer.WSUS.WSUSServer.ConnectToWSUSServer(String ServerName, Boolean UseSSL, Int32 PortNumber) SMS_WSUS_CONFIGURATION_MANAGER 4/23/2015 3:02:37 PM 4756 (0x1294)
Remote configuration failed on WSUS Server. SMS_WSUS_CONFIGURATION_MANAGER 4/23/2015 3:02:37 PM 4756 (0x1294)
STATMSG: ID=6600 SEV=E LEV=M SOURCE="SMS Server" COMP="SMS_WSUS_CONFIGURATION_MANAGER" SYS=GC-VM-SCCM.gcschl.gateschili.org SITE=PRI PID=9148 TID=4756 GMTDATE=Thu Apr 23 19:02:37.625 2015 ISTR0="GC-VM-SCCM.gcschl.gateschili.org" ISTR1="" ISTR2="" ISTR3="" ISTR4="" ISTR5="" ISTR6="" ISTR7="" ISTR8="" ISTR9="" NUMATTRS=0 SMS_WSUS_CONFIGURATION_MANAGER 4/23/2015 3:02:37 PM 4756 (0x1294)
Waiting for changes for 60 minutes SMS_WSUS_CONFIGURATION_MANAGER 4/23/2015 3:02:37 PM 4756 (0x1294)

the error says service unavailable.  Is the WSUS Service running? 

Yes it is running. We reboot the server and it failed on 9th update.

did you see this

https://social.technet.microsoft.com/Forums/systemcenter/en-US/28073fab-2dd3-4647-8ded-c3b4c68a5fd3/smswsusconfigurationmanager-messageid-6600-the-request-failed-with-http-status-503-service?forum=configmgrsum