Hi,
You have wrongly assigned the method. It should not be pointing to Execute method.
it should be something like below
TRY.
CREATE OBJECT proxy.
CATCH cx_ai_system_fault.
ENDTRY.
TRY.
CALL METHOD Proxy-> " GIVE THE OUTBOUND SERVICE INTERFACE NAME HERE"
Exporting
output = t_company_name
IMPORTING
input = t_stock_value.