Screen Blank and Cannot Acces GPO from RSAT Windows Client

I login in windows client and configure gpo wallpaper, but when i login windows client the gpo doesn’t work, i try gpupdate but it doesn’t work, and when i try to access gpo via rsat i can’t access it.
then i check the samba log on ucs and it shows rpc error (librpc ndr pull error)
when I restarted the samba service, everything went back to normal, I want to ask why this can happen, and how to fix permanent it???