MDM API: catches sy-subrc = 3 which is EX_KERNEL_ERROR

experts,

My MDM API code looks as below; but it catches sy-subrc = 3 which is EX_KERNEL_ERROR.. and Message of the error says: NiRaw2ConnectError: Connection refused..

What are the steps to debug this issue? thanks!

(Note: I have posted this query in SAP Master Data Management as well, I dont know if i get response there, thought if anybody who have used API code for WS, could answer me ..)

REPORT  ZPKB_MDMAPI1.

DATA lv_log_object_name TYPE mdm_log_object_name.
DATA ls_config_info     TYPE mdm_config_information.

DATA ls_dbms_info       TYPE mdm_dbms_info.
DATA ls_dbms_auth_inf   TYPE mdm_dbms_auth_info.
DATA lt_repositories    TYPE mdm_repository_info_table.
DATA ls_repository      TYPE mdm_repository_info.
DATA lv_errstr          TYPE string.

DATA LV_LOG_OBJECT_TYPE_CODE TYPE  MDM_TABLE_CODE.
DATA LV_CDT_LANGUAGE_CODE TYPE MDM_CDT_LANGUAGE_CODE.

*Logical connection name for all operations (maintained in customizing)

lv_log_object_name = 'CUSTOMER'.
LV_LOG_OBJECT_TYPE_CODE = 'CUSTOMER'.
LV_CDT_LANGUAGE_CODE = 'ENG'.


CALL FUNCTION 'MDM_ACCESSOR_CONNECT'
  EXPORTING
    IV_LOG_OBJECT_NAME           = lv_log_object_name
    IS_REPOSITORY_LANGUAGE       = LV_CDT_LANGUAGE_CODE
 EXCEPTIONS
   EX_API_USAGE_ERROR           = 1
   EX_PROVIDER_ERROR            = 2
   EX_KERNEL_ERROR              = 3
   EX_SERVER_RC_CODE            = 4
   EX_NOT_SUPPORTED             = 5
   OTHERS                       = 6
          .
IF SY-SUBRC <> 0.
 MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
         WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.


CALL FUNCTION 'MDM_API_QUERY'
  EXPORTING
    IV_OBJECT_NAME                 = lv_log_object_name
    IV_OBJECT_TYPE_CODE            = LV_LOG_OBJECT_TYPE_CODE
*   IT_QUERY                       =
*   IV_HITS_MAX                    =
*   IS_SORT_INFORMATION            =
*   IS_RESULT_SET_DEFINITION       =
*   IV_START_WITH                  =
* IMPORTING
*   ET_RESULT_SET                  =
*   ET_HIER_STRUCTURE              =
 EXCEPTIONS
   EX_API_USAGE_ERROR             = 1
   EX_PROVIDER_ERROR              = 2
   EX_KERNEL_ERROR                = 3
   EX_SERVER_RC_CODE              = 4
   EX_NOT_SUPPORTED               = 5
   OTHERS                         = 6
          .
IF SY-SUBRC <> 0.
  write:/ sy-subrc.

  MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
          WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.

ENDIF.


CALL FUNCTION 'MDM_ACCESSOR_DISCONNECT'
  EXPORTING
    IV_LOG_OBJECT_NAME       = lv_log_object_name
 EXCEPTIONS
   EX_API_USAGE_ERROR       = 1
   EX_PROVIDER_ERROR        = 2
   EX_KERNEL_ERROR          = 3
   EX_SERVER_RC_CODE        = 4
   EX_NOT_SUPPORTED         = 5
   OTHERS                   = 6
          .
IF SY-SUBRC <> 0.
 MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
         WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.