Cannot process message; no node determined : I wanna send mail but i got this error.

WHEN '&MAIL'.

DATA: lt_mailsubject TYPE sodocchgi1.

DATA: lt_mailre TYPE STANDARD TABLE OF somlrec90 WITH HEADER LINE.

DATA: lt_mailtxt TYPE STANDARD TABLE OF soli WITH HEADER LINE.

* Recipients

lt_mailre-rec_type = 'U'.

lt_mailre-receiver = 'rasim.bas@detaysoft.com'.

APPEND lt_mailre .

CLEAR lt_mailre .

* Subject.

lt_mailsubject-obj_name = sy-uzeit.

lt_mailsubject-obj_langu = sy-langu.

lt_mailsubject-obj_descr = sy-uzeit.

* Mail Contents

lt_mailtxt = 'This is a test mail'.

APPEND lt_mailtxt. CLEAR lt_mailtxt.

* Send Mail

CALL FUNCTION 'SO_NEW_DOCUMENT_SEND_API1'

EXPORTING

document_data = lt_mailsubject

TABLES

object_content = lt_mailtxt

receivers = lt_mailre

EXCEPTIONS

too_many_receivers = 1

document_not_sent = 2

document_type_not_exist = 3

operation_no_authorization = 4

parameter_error = 5

x_error = 6

enqueue_error = 7

OTHERS = 8.

IF sy-subrc EQ 0.

COMMIT WORK.

* Push mail out from SAP outbox

SUBMIT rsconn01 WITH mode = 'INT' AND RETURN.

ENDIF.

endcase.