751e44c4__Error_Codes___ServiceNow_Wiki__Description
[Error / Data Code] 49 / 531 [Error] RESTRICTED_TO_SPECIFIC_MACHINES [Description] 
Indicates an Active Directory (AD) AcceptSecurityContext data error that is logon failure caused because the user is not permitted to log on from this computer. Returns only when presented with a valid username and valid password credential.
LDAP Error Codes - ServiceNow Wiki
Description