Some time the group policy on window servers can break, it can be after bad domain upgrade or file corruption or even IT mistake . The domain can suffer greatly from that . In order to restore the values to there default you can use command line “dcgpofix” which will reset all the group policy objects :
You can reset specific target for example to reset domain GPO :
dcgpofix /target:Your_Domain_FQDN
To reset the dc GPO :
dcgpofix /target:Your_DC_FQDN
To Reset both :
dcgpofix /target:both