when i using this function module
call function 'SO_NEW_DOCUMENT_SEND_API1'
exporting
document_data = maildata
* document_type = 'RAW'
put_in_outbox = 'X'
tables
* object_header = mailtxt
object_content = li_objtxt
receivers = li_final
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 <> 0.
MESSAGE 'No Mails Sent' TYPE 'E'.
endif.
i get exception error 6 x_error.
how to find what mistake i done