751e44c4__Error_Codes___ServiceNow_Wiki__Description
[Error / Data Code] 48 [Error] LDAP_INAPPROPRIATE_AUTH [Description] 
Indicates that during a bind operation, the client is attempting to use an authentication method that the client cannot use correctly. For example, either of the following cause this error: The client returns simple credentials when strong credentials are required...OR...The client returns a DN and a password for a simple bind when the entry does not have a password defined.
LDAP Error Codes - ServiceNow Wiki
Description