Error change administrator role in geonode rest role geoserver

[eiacopini]

Hi I tried to change the administrator role to geonode rest role, but the drop-down menu is empty. Now the field is left empty and geoserver returns this error:

java.lang.NullPointerException
	org.geoserver.security.GeoServerRestRoleService.getRoleByName(GeoServerRestRoleService.java:337)
	org.geoserver.security.GeoServerRestRoleService.getAdminRole(GeoServerRestRoleService.java:440)
	org.geoserver.security.impl.RoleCalculator.addMappedSystemRoles(RoleCalculator.java:114)
	org.geoserver.security.impl.RoleCalculator.calculateRoles(RoleCalculator.java:106)
	org.geoserver.security.impl.RoleCalculator.calculateRoles(RoleCalculator.java:67)
	org.geoserver.security.filter.GeoServerPreAuthenticatedUserNameFilter.getRolesFromRoleService(GeoServerPreAuthenticatedUserNameFilter.java:184)
	org.geoserver.security.filter.GeoServerPreAuthenticatedUserNameFilter.getRoles(GeoServerPreAuthenticatedUserNameFilter.java:150)
	org.geoserver.security.oauth2.GeoServerOAuthAuthenticationFilter.doAuthenticate(GeoServerOAuthAuthenticationFilter.java:313)
	org.geoserver.security.oauth2.GeoServerOAuthAuthenticationFilter.doFilter(GeoServerOAuthAuthenticationFilter.java:139)
	org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
	org.geoserver.security.filter.GeoServerCompositeFilter$NestedFilterChain.doFilter(GeoServerCompositeFilter.java:71)
	org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)
	org.geoserver.security.filter.GeoServerSecurityContextPersistenceFilter$1.doFilter(GeoServerSecurityContextPersistenceFilter.java:52)
	org.geoserver.security.filter.GeoServerCompositeFilter$NestedFilterChain.doFilter(GeoServerCompositeFilter.java:75)
	org.geoserver.security.filter.GeoServerCompositeFilter.doFilter(GeoServerCompositeFilter.java:92)
	org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
	org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215)
	org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178)
	org.geoserver.security.GeoServerSecurityFilterChainProxy.doFilter(GeoServerSecurityFilterChainProxy.java:142)
	org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:358)
	org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:271)
	org.geoserver.filters.GZIPFilter.doFilter(GZIPFilter.java:48)
	org.geoserver.filters.SessionDebugFilter.doFilter(SessionDebugFilter.java:49)
	org.geoserver.filters.FlushSafeFilter.doFilter(FlushSafeFilter.java:42)
	org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
	org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)

Thank You